Of all the modes of transport electric railways have proven to be the most successful in providing an alternative choice that entices people to leave their cars at home. With light rail it is possible to combine the attractiveness of traditional railways with the ability to penetrate city centres at street level...
This page looks at light rail, with a special emphasis on showing how it 'dovetails' into the urban environment. Some examples are from new modern installations (ie: opened since the 1970's), others come from upgraded older tramway (streetcar) systems.
First however, a few words about just what 'light rail' is, and why it is the worlds fastest growing and most popular form of urban public transport.
The Toronto LRT Information Page is an excellent website promoting expansion of surface light rail in Toronto Canada rather than the vastly more expensive expansion of the subway system. This website includes detailed cost comparisons which may be of related interest to this page; these can be found here... http://lrt.daxack.ca/LRTvsHRT/CostCompare.html - both links open in new windows.
One only has to see how our politicians are 'fighting shy' of the pro-car lobby to appreciate the lure of the private car and its voting owners. Indeed, nothing attracts the ire of motorists more than the fear of being FORCED off the road and onto public transport. For that reason it is vitally important to go the extra mile in proving that light rail can be a motorists' friend - that light rail and cars can co-exist.
Most people of our era have only known life with the freedom to travel where and when WE choose that comes with having easy access to a car.
And having enjoyed that freedom we do NOT want to live like people did in the pre-war (WW2) period when private transport was rarer.
BUT this does not mean that we do not want to use public transport -- rather it means that for us to use it
the transport must fit our needs, and that if it doesn't then we have the option of voting with our feet.
This includes the ultimate sanction - relocating our lives elsewhere.
The appalling negative effects of this are well documented in American cities where the wealthy have moved out and the downtown cores become dilapidated high crime ghettos.
If even half the power of the pro-car lobby could be tapped into and used for promoting the concept of freedom to be able to choose a viable alternative to having to drive (a concept to which politicians only ever pay lip service - even at election time) then there would be real possibility of alleviating the chronic congestion that bedevils our road system.
Illustrated "index page" image information:-
Click image - or here - to see a larger version in a new window.
Docklands Light Railway (London); Birkenhead Tramway (The Wirral, Merseyside); Nottingham Express Transit;
Blackpool Transport Services Tramway; Tyne & Wear Metro; Croydon Tramlink;
Sheffield Supertram; Midland Metro (Birmingham / West Midlands) Manchester Metrolink.
Direct links to other Light Rail Fits In pages...
Buses are generally suited to flows of up to 6,000 passengers per direction, per hour, above this there comes a point where even a constant
stream of buses every few seconds would not be able to cope with the numbers of passengers.
As a contrast, 'heavy rail' suburban, commuter and metro systems are only economic for flows of 15,000 (or above) passengers per direction / hour;
So, because it is suitable for flows between 2,000 and 20,000 passengers per direction / hour light rail bridges the gap in passenger flows that exist between buses and trains.
|Portland Oregon, USA: Low capacity articulated streetcar of a design which is just 20m (66ft) in length and operates on a relatively short inner-city service.
|Sheffield, England: High capacity articulated tramcar of a design which at 35m (114ft) in length is almost twice as long as the Portland streetcar.|
Both above types of light rail vehicle come from 'modern' (post 1970) systems. When choosing the style of operations for these systems the planners decided that they would use multi-segmented articulated vehicles which would only operate 'solo' / not in coupled formation.
By way of a contrast some long-time-established systems use older style 'rigid' light rail vehicles, either on their own or with two (or more) coupled together. Typically these vehicles will be used until life-expired - when they will be replaced with multi-segmented articulated trams / streetcars - although very occasionally other limitations may result in exceptions to this generalisation. For instance: in the Japanese example seen here the depôt and all platforms would first need rebuilding to accept longer tramcars - which explains why they are still building this style of LRV.
|A pair of older 'rigid' tramcars coupled together in Prague, Czech Republic. These are 14m (46ft) in length.
|A modern (built in 2009) 'rigid' light rail vehicle which is just 13m (42ft) in length on the Tokyo, Japan, Toden Arakawa Line
Varying 'Train' Lengths: Single, Double & Triple Unit Services.
|A single unit service on a chilly, wet Sunday morning, when traffic would be very light.||A twin unit service.|
|A triple unit service.||Another city that also varies 'train' lengths is Düsseldorf, Germany. This video-still shows a triple-unit on a route which links the exhibition centre with the main railway station.|
The single/double/triple-unit images come from Calgary, Canada; and show different train lengths using the same type of single articulated light rail vehicle (LRV) which is 24m (79ft) in length. Calgary is a popular city with a fast growing population, and to cope with rising passenger numbers it has been decided that the station platforms will be lengthened to facilitate the use of quadruple (4) unit trains.
In Düsseldorf, Germany, the three-unit services operate when there are major events at the cities' exhibition centre. As this camcorder still clearly implies, despite its 80.7 metre length (each individual vehicle is 26.9 metres long) sharing a public highway that is open to all traffic poses no problem.
A video showing triple unit / 3-car light rail services travelling as street trams in Kaiserswerther Str, Düsseldorf has been placed on the 'youtube' file-sharing website and can be watched (in a new window) by clicking either the projector icon or this link - http://www.youtube.com/watch?v=_JuEVk8d4GI
Ultra Light Rail.
For the lowest of passenger capacities there is something known as ultra light rail which is themed on the concept of small low capacity "cabin" sized vehicles running on lightweight (perhaps narrow gauge) tracks. "Cabin" transports are looked at on another page.
One of the many advantages of lighter vehicles such as these is that their lower axle loadings would mean that shallower foundations would be needed for the tracks, considerably reducing both the cost and the time duration of their installation. It is expected that it would cost just £1m per km to install this system (compared to about £6m for other types of light rail) making it one of the most cost effective rail-bourne technologies available.
Although the first fully working (and British built!) prototypes were built in the early to mid 1990's it was only in 2009 that the first of these ULRV's entered service on a commercial basis.
The Passenger Train Variations - Trams, Streetcars & Light Rail Vehicles page includes a look at the different types of light rail vehicle in greater detail.
The Parry People Mover features what could be seen to be the "minibus" of light rail transit, making it ideal for lower capacity routes.
These images show two slightly different variants of the Parry People Mover tramcars, this being the PPM50 in 'low floor' format (left) which is more suited to street based systems and the PPM60 in 'high floor' format (right) which is more suited for services that serve railway-style 'high floor' stations. It is in this latter guise that the first commercial service is being operated, with there being two Parry railcars replacing mainline railway trains on a short branch line in Stourbridge, West Midlands. To maintain overall passenger capacity and even cope with higher passenger demand the PPM services operate at a higher frequency than the mainline railway trains.
The image on the left was sourced from the Parry People Mover website http://www.parrypeoplemovers.com/ - link opens in a new window.
A video showing several different types of Parry People Mover vehicle on demonstration and in public service in Stourbridge has been placed on the 'youtube' file-sharing website and can be watched (in a new window) by clicking either the projector icon or this link - http://www.youtube.com/watch?v=M28tGs253NM
Fitting In 'Anywhere'.
Everyone knows what trains are about. And how they can operate underground, overground, over bridges, through tunnels, cuttings, etc, etc,. Light rail can do all this too. But because light rail vehicles are usually of smaller dimensions and lighter 'mass' they can also go places and do things that traditional trains would find either difficult or outright impossible.
One of these is take to the public highway and use it to travel through the town at street level, following the existing street pattern. Even though this usually requires the complete rebuilding of the roadway (to move underground utilities - ie: electricity, gas, telephone and water, so that their future maintenance will not disrupt the transports) the street environment is still one of the cheapest options.
Of course there are alternatives, such as the wholesale demolition of many buildings to create new surface transport corridors or creating new elevated transport systems, however whilst this was often done for new roads - at least until the public protests against it became too vociferous - such is not normally seen as a viable option for urban public transport. Therefore for built-up, often historic city centres the only other realistic option is to put the transport underground, however whilst this is sometimes adopted it is just about the most expensive option and therefore only done where absolutely necessary.
Sometimes light rail will behave just like 'heavy rail'.
Away from the street environment and when operating inter-urban (cross country) services many light rail lines will look (to the casual observer) little different from a 'heavy' or 'mainline' railway. This especially applies to sections of route which use railway-style sleeper track with ballast and multi-wire overhead power supply wiring. Perhaps the only give-away would be if the line is unfenced, as whilst (here in Britain) this is a legal requirement for the mainline railways, it remains an optional feature for light rail.
Depending on service frequency, available space, and even available funds when the line is built, these lines may be formed of either bi-directional single track or twin track.
A single track inter-urban light rail line with tramway-style single wire catenary running alongside a local road.
A double track inter-urban light rail line with railway-style multi wire catenary flanked by a shared cycle + foot path.
|Even with the presence of the light rail vehicle few casual observers would spot much difference between this and a 'heavy rail' location. Both have similar - looking tracks, multi-wire overhead (catenary) wiring, etc.
This is the Stuttgart, Germany 'Stadtbahn' (ie: 'city-railway'). Its origin is the former street tramway (straßenbahn) system which over a 27 year period ending in 2007 has been upgraded / rebuilt to the present-day rapid-transit status.
It could be said that many British towns and cities would have been wiser to have adopted similar long-term plans, rather than hastily replace their trams with diesel buses.
|London is famous for its underground 'tube' railway and included in this system are several tube-style subterranean sections of the Docklands Light Railway.
Whilst the DLR uses light rail vehicles its fully automated 'driverless' mode of operation is exceptional for a light rail system.
Although implementing tunnel systems is the most expensive way of creating new lines the shorter trains (and hence, shorter platforms) still provide cost savings compared to 'heavy rail' systems.
Sometimes light rail will behave just like traditional street trams / streetcars.
Typically when operating in 'street tramway' mode newer light rail services will be routed via quieter roads which are either prohibited to the general traffic or intended for local access only, with other major roads taking the through traffic. By way of contrast existing (often upgraded) light rail services will use local streets as appropriate. By virtue of their having 'been there' for many years the situation is often different with these 'historic' systems.
|'Traditional' street tramway in Gent, Belgium. This historic tramway system has seen in over 100 years of continuous operation and in addition to the type of tramcar seen here also operates some multi-segmented articulated trams.||Some former London Docklands Light Railway vehicles operating on one of the 'street tramway' sections of a light rail route in Essen, Germany.|
A different type of 'street tramway' mode is where new (and often historic) systems travel through the city's central business district. In cities where street-based shopping centres still exist these will usually be pedestrianised zones where pedestrians can wander freely - including over the tracks. If motor vehicle access is required (for instance: to service local shops) this will usually be restricted to late evenings, or early mornings. Elsewhere these are often known as 'transit malls' (especially in American English) and are usually regarded as normal roads upon which there is a public transport / transit only restriction, and except when crossing the road pedestrians will be required to keep to the footpath / out of the roadway.
The purpose of street-based transit malls is usually either to provide a rapid congestion-free route for the public transports (as alternatives to building underground / subway systems) or to focus the transports on one corridor through the city centre / downtown core. Whilst these concepts are usually seen as being beneficial with respect to improving access to the areas served and creating a focus for inward investment, the 'down' side is that if the transport is too successful and the number of routes (lines) and service frequencies using these malls increases then it can result in them becoming congested. In some cities, such as Dallas (USA) and Karlsruhe (Germany) the chosen solution is to relocate at least some of the transports underground (at the time of writing neither city has actually started building works). Manchester (England) is adopting a different solution; they plan to create a second surface route using alternative nearby streets. One city which has already done this is Portland (Oregon) where the second (surface) city route opened in September 2009.
|A DART (Dallas Area Rapid Transit) light rail service passes the old Post Office and Court House as its travels through the Downtown Transitway Mall.||One of Europes' most successful new street tramway systems is in the French city of Strasbourg, where large segments of the city centre road system has been converted into tramway and pedestrian zones, although motor traffic is still admitted, for 'access-only'.|
|Despite it looking like any normal urban street a local law in Dallas prohibits pedestrians from crossing the Transitway Mall in the usual way. Instead it is only permitted to cross the road
at designated 'cross walks', which typically would be at traffic signal controlled locations. Even though it can mean a long detour - especially if the place one wishes to go is 'just across the street' - simply
using ones' eyes to ensure that nothing is coming / the road is clear and then crossing to the other side is an illegal act. Apparently this situation has arisen because of an old law which says that the tracks
and the land they are on are property of the railroad - with crossing (aka: walking on) the tracks at unauthorised locations being seen as tresspassing.
BTW, 'cross walks' is an American phrase which apparently refers to authorised crossing points and not angry walkers, although this bizarre terminology and the 'do not cross the road' 'diktat left one British visitor feeling very bemused - thankfully however it was a kindly transit official and not a jobsworth police officer who explained about the law - as this resulted in the usual (short-ish) period of detention plus financial penalty not being levied. Some cities are best not revisited.
Pedestrian zones and transit malls are looked at in greater detail on the Light Rail, Pedestrian Zones And Transit Malls page.
Street-based segregation: one of the keys to success.
Although when travelling in the street environment light rail can share the traffic lanes with the other traffic it is usual, if the road is wide enough, for it to benefit from its own dedicated lanes (or 'rights of way'). The advantage of this is that it helps the service to operate reliably with the minimum of delay from the general traffic.
Where there is segregation the ways in which this can be achieved can vary - the most successful options have proven to include painted lines, raised sections of kerb or raised sections of roadway. However, light rail's adaptability to local circumstances means that the possibilities and permutations are endless, if effective they all are correct, what is important is that the other traffic is deterred - but not in the case of absolute necessity (for example: to pass a parked delivery vehicle) prevented from using the portion of the road reserved for the public transport. There are no fixed 'rules' - it all depends on the location.
|Raised section of roadway on an urban road in Bordeaux, France. This road is similar (in width) to many urban roads in Britain.||Raised section of roadway on a much wider urban road in Karlsruhe, Germany.|
|A road in Brussels, Belgium, where painted lines delineate the tram-only right of way. In the distance can also be seen a solution for tree-lined central reservations, with the trams using segregated adjacent road lanes instead of actually travelling on the grassy reservation.||Raised section of kerb in Amsterdam, Holland.|
The Swiss city of Zürich is reputed to have the (western world's) most successful urban transport system, with the public transports attracting over 50% of all journeys within the urban area
At its heart is an integrated network of electric street transports (primarily trams plus some trolleybuses and suburban light rail) as well as electric 'heavy' (mainline) suburban railways.
As part of environmental policies designed to protect the health of city-dwellers by minimizing urban air pollution motor buses are generally restricted to outer suburban and rural services.
Transport integration is looked at on the Transport Integration page.
Most of the tramway system in the Swiss city of Zürich operates along dedicated lanes on urban streets which are shared with the general traffic. Combined with traffic signals which often change in favour of the trams as they approach these features make for a transport system where journey times and adherence to the timetable almost equals that of underground railway / metro / subway systems.
Sometimes the optimal form of segregation will be along the sides of the roadway, rather than in the centre.
|This road in Helsinki, Finland, demonstrates a location where both tracks are on one side of the public highway.||By way of a contrast this road in Turin (Torino), Italy demonstrates a location where the tracks are split from each other and travel in segregated kerbside lanes.
Note the different styles of segregation; in the foreground this is of the type which can be accessed by other traffic whilst under the trees the steel wheel and rubber tyred transports are physically separated.
More from Turin, Italy, showing a kerbside right of way segregated from other traffic by large road studs which have been embedded into the road surface. The red flaps are only at the entry points to the individual sections of reserved lane and in a country where most road users reserve the right to act according to traffic conditions they help to remind them to travel in the correct traffic lanes.
Sometimes there is only a need (or roadspace) for one direction to benefit from proper segregation, so LRV's travelling in the other direction will share roadspace with the general traffic.
In situations such as Stuttgart below left traffic signals located where the light rail joins the roadway can hold back the general traffic for a few seconds to allow an approaching LRV to continue its journey without delay.
|Examples of partial segregation.|
|Road centre in Stuttgart, Germany.||Side of road in Bern Switzerland.
The LRV seen here is in the dedicated lane, trams travelling in the opposite direction use the regular traffic lane. The tracks can just about be seen in the road surface - this is easier to see in the clickable larger image.
|Cars demonstrating how simple methods of segregation make it possible to briefly stray into the reserved right of way to pass an obstruction. Images show a road centre / raised kerb example from Amsterdam, Holland (left) and a side-of-road / painted line example from Geneva, Switzerland (right).|
|Some more examples of why there is sometimes a need for the reserved right of way to be accessed by other road traffic.|
|A section of road where painted lines protect the tram lane. The orange telecom / utility van is illegally parked (possibly for want of somewhere legal?) and the vehicles are waiting for the LRV's to pass first before they can go around the obstruction. The location is Düsseldorf, Germany.||A section of road where differently coloured road paving gives the effect of painted lines and again illegal parking means that access is required over the tracks. In this instance it is a school bus (with amber - not red - lamps flashing) that is causing the obstruction. The location is Portland, Oregon, USA. The road seen in this image is for one-way traffic only, traffic travelling in the opposite direction uses a parallel road.|
The two images above are video-stills - clicking either of them or the projector icon will download a hand-held 29 second video clip named 'Passing-parked-vcls320.mpg' which shows the action being described.
The Light Rail And Compatibility With Parked Vehicles. page looks at solutions related to on-street parking in greater detail.
Sometimes complete separation is possible, however this is only a good idea if the roadway has two (or more) lanes. This is important as it will allow a stationary (perhaps broken down) road vehicle to be passed by the other road vehicles. Furthermore, with 'single track' roads there would also be the possibility of the emergency services being delayed because they were caught behind the other road traffic without being able to pass.
|Examples of full 'road centre' segregation.|
|In the median of a dual carriageway (divided highway) in Paris, France.||In the median of an urban motorway in Essen, Germany. This line was built as one combined construction project at the same time as the urban motorway and whilst this may seem like a sensible idea it is also something which the British treasury's funding regulations do the upmost to prevent. Funding is looked at on the Enough stick - how about some carrot page.|
|Examples of full and partial 'side of road' segregation.|
|A suburban light rail line with both tracks on one side of the road on the outskirts of Zürich, Switzerland.||A location where the tracks are on either side of the traffic from which they are physically separated by a low hedge in Turin, Italy.|
Interlaced / gauntlet track and bi-directional single track.
Other solutions for where space is at a premium can include short sections of either single or interlaced (gauntlet) track. Sometimes this will be done as an alternative to sharing the road with the general traffic at a location where there is insufficient width for twin tracks, other times it will be adopted for different reasons, such as to pass through a space constricted location or to cost effectively serve both platforms at an end of line / terminus station.
The principle difference between interlaced and bi-directional single track is that with interlaced tracks the transports retain their directional individuality (this is further explained below). Both impose the same restriction with respect to transports travelling in opposite directions not being able to pass each other / having to wait their turn.
Note that this section does not look at the use of single track in the context of where services travel along different streets, often times as part of a one way traffic system.
Interlaced track left and single track right in Amsterdam, Holland.
Note how the example on the right creates space for parked delivery vehicles.
With the examples seen above both types of track occupy much the same ground width, however some of the other examples seen below use interlaced tracks which are set apart by a small distance. As ever, there is no fixed 'rule', it all depends on the location and what the track planners need to achieve.
|Closely-spaced interlaced track in Prague allows two-way services to travel through an historic narrow arched passageway.
|More widely spaced interlaced track allows two-way services to travel under a space-constricted road bridge and through a deep cutting in south London.|
The example above right comes from a location where there has been a railway of some sort for approximately two hundred years. Over the years the brickwork weakened and when one of the retaining walls on the other (but inaccessible) side of the bridge became in danger of collapse it was found to be cheaper to shore it up with massive concrete buttresses. Years later, when Tramlink was constructed, the planners decided that it would be more cost effective (aka: 'cheaper') to use interlaced track rather than rebuild the wall so that normal double track could be installed.
Interlaced / Gauntlet track and single track comparisons.
There are no fixed rules regarding which would be chosen for a location, but as a general theme interlaced track (ie: one inside the other) will be used for shorter distances and bi-directional single track for longer distances. Both occupy similar 'footprints' (land take).
Therefore it could be said that 'everything else being equal' there is a tradeoff between the cost of four rails and the cost of points / turnouts / switches. There is presumably an optimal length of line where one becomes more economic than the other, so often it will be for the people who look at the financial aspects of installing the physical infrastructure to decide which will be used.
A video showing some of the sections of interlaced and single tracks seen here has been placed on the 'youtube' file-sharing website and can be watched (in a new window) by clicking either the projector icon or this link - http://www.youtube.com/watch?v=jOTnmci9dJA
|Basle, Switzerland: Interlaced trackage on a roadside line at a pinch point where there is not enough space for double tracks. Not seen are the signals which ensure that only services travelling in one direction at a time try to use this section of track. Note the access across the line, protected with level crossing style flashing lights.|
Although it may look somewhat similar, interlaced track should not be confused with advance splitting / junction pre-selection. This is usually used where routes diverge, and the idea is to prevent passing motor traffic from damaging the moving switch blades (etc.,) by splitting the tracks for the different routes at a location where the moving parts are not in a busy traffic lane. The example shown here comes from Croydon Tramlink (England).
Other reasons for single track.
Single track is also often favoured as a way to save money when building a new line and it is felt that service frequencies will allow this type of track layout without impinging upon reliability. If need be then passing loops (short sections of double track which allow services to pass each other) can be located along the single track section. Sometimes these will be located at stations. With bi-directional single track tight scheduling is often required to prevent one service from being delayed whilst waiting for an approaching service to pass through the single track. There can also be problems if ridership increases to the point whereby a more frequent service is required - but the track configuration does not allow this. It is not unknown for what seems like a 'cheap' solution to later need remedial work which ends up being more expensive in the longer run. However if headline construction costs are all that matter then this can be a necessary evil.
|The start of a single track section on the Croydon / London Tramlink service.||A passing point on the Croydon / London Tramlink service - on a route which is alongside the mainline railway. The passing point ends opposite the mainline train.|
The image above left was taken at a tramstop which doubles as a passing point at the end of a section of single track bi-directional tramway. Note how the departure of service is being delayed whilst it awaits the approaching tram to clear the single track. This route was previously a little-used mainline railway branchline which operated trains at 44 minute intervals, and since its conversion to tramway passenger numbers have risen so much that at peak times overcrowding often prevents passengers from boarding at some tramstops. Increasing capacity by lengthening the trams or operating double units coupled up would require every stop en route served to be rebuilt (made longer) - which would be expensive - whilst the other option of increasing service frequency has been inhibited by the length of some of the numerous sections of single track. Apart from two bridges single track was only used on this route as an economy measure to reduce headline construction costs.
The image above right was taken on a different branch where the single track was installed because the light rail incorporated one track from (yet another) infrequent mainline railway route and this was the only way to fit the two railway services into the available space. (The mainline railway also now operates as a bi-directional single track). This photograph was taken from the walkway for one of the newer 'more local' halts added when the light rail was installed. Normally passing places would be located at tramstops - as is done at a different tramstop nearby - but at this specific location there simply was not enough space. Because the mainline railway is electrified using the third rail system so extra security measures have been used to discourage walking on the track. This includes the saw-tooth style wooded planking seen at the bottom of the image.
The locating of mainline / 'heavy' rail and light rail in close proximity so that they share the same transport envelope is known as 'route sharing'. This is topic which is more fully explored on the Track Sharing & Route Sharing page.
Sometimes the connection between the tracks which comes from single tracks can also serve other purposes. Interlaced track cannot be used to reverse the direction of travel (aka: 'turn back') a tram. By way of contrast a single track section will have the same operational capabilities as a crossover, which is a short section of track which allows a rail vehicle (of any type) to switch from one running line to another running line - and often then travel in the opposite direction, back to from where it just came. Rail-based systems benefit from crossovers to maintain operations on the rest of the system should one part be blocked, for example for engineering works or due to an accident.
Sometimes short sections of single track are located in front of terminal / end of line stops which feature twin tracks, as it avoids the need for an X shaped crossover or other forms of linking tracks which enable the transport to use two (or more) terminal tracks. The saving would come from there being two sets of points instead of four - although the downside would be reduced operational flexibility in that only one vehicle could enter or leave the station at a time. The image seen below left shows a 'stub' type terminus, where the tracks end at buffer stops. Only certain types of light rail vehicle can use stub end termini, this is further explained on the Passenger Train Variations - Trams, Streetcars and Light Rail Vehicles page.
|A section of single track splits to service a twin-track 'stub' terminus station with an island platform.||A crossover - simply a section of track which allows a rail vehicle to cross from one track to another. Sometimes this is done in conjunction with the rail vehicle reversing direction of travel.|
Compatibility With Roundabouts (Traffic Circles).
There are several ways in which light rail can fit in with the other traffic at roundabouts / traffic circles. These include underpasses / flyovers, which completely separate the public transports from the other road traffic, joining the general traffic and travelling around the circle (part or full way, as required by the route served) or cutting a swathe straight through the centre. This section focusses on the latter two surface / at grade options.
The first images show various options for where the trams travel around the circle with the rest of the traffic. This represents a solution for where several routes use multiple roads to enter and leave the roundabout.
As many of these images show, there is frequently no real need for traffic signals to control the traffic as it enters and circumnavigates the roundabout. Instead the roundabouts can operate as they were designed to, with free-flow being the order of the day. For most roundabouts this represents the optimal traffic management solution. Many traffic planners seem to see traffic signals as some kind of holy grail whilst dismissing their potential negative side effects, which includes adding to traffic congestion and local air pollution (from motor vehicles), etc. Some form of signalisation would only be beneficial at the busiest of locations / times when congestion occurs by itself and even then only if it helps minimise possible delays whilst the tram queues to enter the roundabout.
By way of a contrast, where the trams travel straight through the centre of the roundabout some form of traffic control is required to permit the light rail to cross the other traffic flows in safety. However, as the last examples show, there is still an alternative to full and expensive signalisation of the whole roundabout.
|These views from Amsterdam, Holland, demonstrate how on large roundabouts the transport can follow a segregated path along the inside edge. The image on the left shows that a tramstop has been located within the roundabout, whilst the image on the right shows that the raised kerb type of segregation is being used here.|
|Turin, Italy - a variation on a theme: Here the trams follow an unsegregated path around the outside edge of the roundabout.|
|A third variant can be seen at this roundabout in Brussels, Belgium. Here the trams still travel around the circle, but through the centre of the traffic lane. As there is much pedestrian traffic at this location the roadway entry / exit points feature traffic signals (not visible in this photograph), which explains why the vehicles behind the tram have formed a queue. The trams too are required to observe these signals.||The view from inside a Basle, Switzerland, light rail vehicle showing a roundabout where the transport cuts directly across the traffic flow and through the central circle.
In situations such as this some form of signalisation is highly desirable, both to ensure safety and give the transport priority through the junction.
This Bordeaux, France, roundabout demonstrates a different type of signalisation compared with the solution seen in the Basle image seen one row up right. Here too the trams travel across the central circle (as seen above left) and for safety red warning lights located on the roundabout itself flash when the tram approaches, giving it priority to pass through across the other traffic flows (as seen above right). In many ways the theme is the same as a level crossing. However except for where the tram and other traffic interact there are no other forms of traffic control.
Fitting In With Busy Road Junctions.
Of course whilst travelling along (or on reserved rights of way in close conjunction with) city streets so the light rail will encounter and need to traverse busy road junctions. It is not inconceivable that the services may sometimes have to 'wait their turn' in the traffic signal phasing and / or travel through the junction at the same time as the general traffic travelling in the same direction. To minimise the delays many cities will programme the traffic signal computers to offer them priority.
To reduce the possibility of road traffic becoming confused and mistakenly following signals which are dedicated to the public transports many light rail systems use visually distinctive signals. Depending on the city these special signals may be used throughout the entire system, or just within the street domain with traditional railway-style colour light signals being used elsewhere.
This feature especially applies to new light rail systems, and if it does not already exist is often added to upgraded 'historic' systems as well.In this photograph the signal head on the left is for services which turn left here, whilst the other signal head is for services which continue alongside the main road.
From the top working down the indications are...
Dedicated light rail signals where two routes diverge and follow different roads at a busy road junction in Stuttgart, Germany.
See text left for further information.
The significance of the countdown timer is that this location is also a passenger stop / station, and to make effective use of the limited time slot in the traffic signalling sequencing the traffic signal computer wants the LRV driver to have the passenger doors closed and be ready to depart immediately the equivalent of a green signal is offered.
The signal heads are of course angled for clear visibility for the LRV driver - and not people standing on the footpath photographing them!
Traffic signals and light rail is looked at in greater detail on the Road Junctions, Level Crossings And Traffic Signal Priority page.
Examples Of Negotiating Steeper Gradients & Sharper Curves.
|San Francisco, USA:
Negotiating a steeply banked / curved / graded section of line.
|Portland, Oregon, USA:
A MAX LRV takes city street corners with ease.
Negotiating a steeply banked / graded section of line.
Modern articulated LRV's negotiate corners with ease.
More Examples Of Fitting In With The Urban Environment.
Crossing one the cities' many lifting bridges.
Located between a footpath and the road this tree-lined section of trackage features lawn track, creating a green corridor through the urban jungle. These features are further explored on the Lawn Track - Creating Green Corridors page.
|Route U17, Essen, Germany:
Left: A short section of shared trackage on a narrow road bridge.
Right: Traffic signals protect a junction on a section of bi-directional single track alongside a narrow road. The light rail vehicles use "white" aspects - seen towards top right of picture. Specialist light rail traffic signals are looked at on the Road Junctions, Level Crossings And Traffic Signal Priority page.
The two images above are video-stills - clicking them (or the links below) will download hand held video clips showing the actions being described.
*This link is for a 70 second video clip named Essen-U17-bridge320.mpg Note the wig-wag flashing lights just before the LRV joins the bridge. This video clip also extends a little beyond the bridge, showing the double track light rail formation alongside the roadway, as a 'lead in' to the next video clip.
*This link is for a 59 second video clip named Essen-U17-single-track320.mpg showing the same light rail route a short distance beyond.
|Fribourg, Germany: Part of a city-wide combined walkway / tramway / cycle path route away from motor traffic.
The section (left) leads to a bridge over the main railway station
(right) where there are steps leading down to each of the platforms.
|Karlsruhe, Germany: A new inter-urban line built close to pre-existing housing. With concrete baffles overgrown by climbing plants it is possible to maintain the householder's privacy in a visually attractive way.||Stuttgart, Germany.
A private right of way past some residential properties which have access ramps over the track.
Paris, France: A new section of tramline (route T1) built as an integral part of a new development.
Fitting In With The Weather.
Many light rail systems are located in places where during the winter snow and ice are commonplace, so they prepare for such weather! Even though in the most extreme circumstances there might still be be some disruption as a general theme it will be minimal. Indeed it is often a matter of civic pride to ensure that the transport keeps on working, no matter what the weather throws at it.
|A specialist winter (snowy) weather snow broom in Susukino on the Sapporo, Japan tram system.
|Swedish winters are always snowy, weather which Stockholm's 'Nockebybanan' light rail line takes in its stride.
These vehicles are coming from Alvik station where the passengers benefit from cross platform interchange with the Tunnelbana (Underground Railway) The 'X' crossover seen here enables the trams to 'drive on the right' for the main portion of their route.
Fitting In With Urban Regeneration.
Sometimes new light rail lines are built as catalysts to aid urban renewal. Experience has shown that by politicians and / or the local community installing / investing in new light rail systems in run down, dilapidated inner cities, property developers will also invest their money on refurbishing existing buildings and creating new residential and commercial developments within easy walking distance of the new transports. The often used 'buzz words' for this type of sequence of events include 'virtuous circle', synergetic developments and 'win win' scenario.
|Anatomy of a city reinvented and revitalised - credited to light rail: Portland MAX (above left), unity square - with MAX train in the street behind the square (above right) and Streetcar (below right).|
Portland (Oregon) used to known as one of America's dirtiest cities. Now it is one of the cleanest. The building of the MAX light rail line led to urban renewal in formerly derelict inner city streets and the creation of an attractive city square - which replaced a car park that was rendered superfluous by the new transport. Following this Portland went on to add several more lines to the MAX system and create the first new true streetcar service in the USA since WW2.
MAX and the streetcar are separate entities which serve different streets. In Portland's central business district they both serve the 'fareless square' in which all travel is free of charge. Fareless CBD's exist in several other North American cities as well.
The Portland Streetcar line bucks all the usual themes for new light rail systems.
See text below for further information.
The Portland streetcar bucks all the usual themes for new light rail systems, with the system being mostly on-street using roadspace shared with other traffic and only benefiting from traffic signal priority at a few locations where required to make certain turns. The streetcar vehicles are shorter and narrower than those of MAX, and at 40mph (65km/h) have a lower top speed than the 55mph (90km/h) which MAX achieves. Being at the 'lighter' end of the light rail gamut the streetcar's tracks are also of a lighter and shallower construction, having a railbed of only §one foot (30cm). These design features helped minimise construction costs and disruption to traffic flow and parking, but also mean that travel times are slightly longer than they would have been had the line been built to what could be seen as 'full' light rail standards.
§Some new light rail systems double or even triple this depth, depending on the expertise / experience of the people involved in its design and construction.
Despite these apparent disadvantages the streetcar has been very successful. Costing less than US$60 million its simple presence has attracted many young urban professionals to live near to it. It has been credited as having attracted over US$1.6 billion of inward investment - something which is very unlikely to have been achieved with a bus service! Since first opening the original starter line has been expanded several times, and at the time of writing (November 2009) the expansion is continuing.
For the record, because some people are bound to be curious, whilst the streetcars are capable of travelling on MAX's tracks the reverse is not possible, as the MAX trains would be too heavy and incapable of negotiating the sharpest curves on the streetcar system.
|In London the Docklands Light Railway was built to help regenerate the derelict Docklands area. Since this picture was taken two more towers have been erected alongside Canary Wharf which is seen in the background and in order to facilitate an extension the DLR has been relocated underground.||Often part of the cost of new light rail lines goes on 'urban niceties' (such as this Grenoble, France water feature) and as such increase the apparent cost of installing the transport. The total amounts of money involved may only be very small (barely a percentage point of the cost of the entire scheme) but the beneficial effects can be significant. However the British method of funding public transport investments often inhibits even this.|
Direct links to other Light Rail Fits In pages...