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The next big mistake?

written by andy on

If you ride Muni Metro, you should notice that it is a system that has high platform stations (all underground stops and stops along the T Line) and low platform stations (street level stops west of downtown). The steps change when trains entering and exiting the subway. The dual platform height has been the standard since the Market Street subway was open in around 1980, when old streetcars that ran on the surface of Market Street was rerouted to use the subway. At that time, engineers wanted level boarding in downtown but low floor vehicle was not available. Vehicles with movable steps allows high platforms in downtown and street level boarding in the west side.

For more than 35 years, Muni Metro has had reliability issues. One of the factors contributing to poor reliability is the use of movable steps. Some advocated that Muni should change to low floor vehicles and convert high platforms to low levels. However, Muni is building more high platforms for the Central Subway extension as well as purchasing a 3rd generation of high floor vehicles with movable steps. This time the manufacturer claims that their doors would be more reliable. Let’s see what happens.

For many agencies that built light rail in the 1980s, they also had challenges in meeting accessibility and level boarding. Their first generation vehicles were high floor, but use low level platforms throughout the system for a better pedestrian accessibility and appearance. Many of them, including VTA, chose the path of low floor vehicles.

As Caltrain is pursuing electrification, Caltrain is considering various options for floor heights and door configurations for new electric vehicles. It is doing so because some advocates have expressed desire for level boarding as well as common platform height with high speed rail. It is a complex decision. There are no simple choices. A wrong decision would a ripple affect on train operation elsewhere and impacts to other cities.

Do we really need platform compatibility with high speed rail?

All the mainline trains in California are double deck, but HSR staff dismissed double deck HSR even there are real world examples in Europe and Japan.

If it is just an issue of level boarding alone, it would be an easier issue to resolve. Since agencies like VTA chose the path of low floor vehicles, Caltrain can achieve level boarding by raising platforms to the height of the bottom floor of the vehicle (25″ top of rail). The Front Runner commuter rail system in Utah uses rail vehicles similar to Caltrain and offers level boarding with a higher platform.

High speed rail compatibility adds another dimension. Despite the availability of double deck high speed trains in Europe and Japan, high speed rail staff doesn’t think that these vehicles are fast enough or have long enough service record, and prefers traditional single deck designs. With double deck trains, doors could be located on the bottom level to match low platforms, but single deck trains essentially require the use of high platforms for level boarding.

It is commonly assumed that if HSR chooses single deck trains and high platforms, Caltrain should have vehicles that can use high platforms for both agencies to share platforms. On the other hand, while Caltrain and HSR will share tracks along the Peninsula, both systems don’t necessarily have to share platforms and stations.

What are benefits of common platform heights between Caltrain and high speed rail at various Caltrain/HSR stations:

Non compatible platforms Common height platforms Space to provide additional platforms?
Transbay Terminal – 6 tracks and platforms are to be built at this location. As currently planned, 4 of them would be high platforms for HSR and two low platforms for Caltrain. Track limitation may reduce the amount of Caltrain service that can be provided to Transbay. Allows more flexible use of the facility. Site is constrained and is a very expensive proposition if it is feasible at all.
Millbrae Dedicated platform would be needed for HSR. Some plans show a tunnel with an underground platform for HSR, but in reality a pocket track is more than enough and there’s space to the north and south of the station for that. A single platform in each direction is technically enough, but dedicated platform may still be preferable for operational and customer service reasons. Space is available.
San Jose Dedicated platforms would be needed for HSR. Even with the ability to share platforms, an expanded station may still be needed for capacity, operational, and customer service reasons. Space is available.
Other Caltrain stations Allows high speed rail use in an emergency but will be non-level. Provides no daily operational benefits. Allows high speed rail to use platform on an limited or emergency basis. If there’s space it would help HSR by allowing them to overtake Caltrain.

Design options and trade offs

There are few options to provide level boarding and common platform heights. Almost all will require some kind of design and operational compromises for Caltrain, either on an interim (until the time all platforms are rebuilt) or a permanent basis (even after all platforms are rebuilt).

Low platform only Single level train Trap door or movable steps Doors with floor at two different heights
Examples Other than mock ups there’s no real world examples that I know of.
Capacity High Low. Need longer trains and/or 3+2 seating to compensate for capacity High Moderate to high. Seats removed for extra doors
Level boarding height around 25″ around 50″ around 50″ One set of doors at around 25″ and another at 50″
Share platforms with HSR at Transbay (if HSR uses single deck trains) No Yes Yes Yes
Access from current 8″ platform 2 steps 4 to 5 steps 4 to 5 steps 2 steps
Wheelchair access from level platform Level access to wheelchair area Level access to wheelchair area Level access to wheelchair area. If wheelchair rider needs to exit at a station that has a different platform height than the one he or she boarded. That rider will need use an interior lift.
Wheelchair access from current 8″ platform Mini-high is needed. Lift or large ramp is needed. Lift or large ramp is needed.
Bike access from level platform Level access from door to racks level access from door to racks No level access from high platform stops if storage is located at the lower level. Storage at mid-level will significantly reduce capacity.If stored at the lower level, cyclists will have to take their bikes up and down interior steps, creating a safety issue and increase dwell time.
Bike access from current 8″ platforms(fewer steps are better) 2 steps access to racks 4-5 steps access to racks 4-5 steps to access trains, another 3-4 steps to access racks if they’re located at the lower level. 2 steps access to racks. If the cyclist need to exit at high platform stops, rider will need to take their bikes up interior steps, creating a safety issue and increase dwell time.
Require other non-HSR stations to use 50″ high platform for level access.(No is better) No Yes Yes No

Going up the steps to board the train and then go down the steps to the lower level. Is this an acceptable way to handle bikes?

It is important to note that it is not just about the level access between the platform and just any part of the railcar. It should be about level access to the part of the railcar where it offers the most capacity particularly for bikes and wheelchair. If they have to navigate steps or require crew assistance once inside the train, it defeats the true intent of level boarding. There are some less able-bodied riders who take bikes on the trains today and have difficulty even navigating the steps at the door. To me requiring them to navigate steps with their bikes inside the train is a fatal flaw, even without steps between the railcar and platform.

While theoretically all Caltrain platforms can be rebuilt at high speed rail height, it can face community opposition for aesthetic reasons, considering that many of the stations are historic. If the intent is for Caltrain to adopt high speed rail height and use it at all stations, it needs to be communicated and supported by the communities. Any kind of actions that can be perceived as a backdoor deal can invite blowback, as witnessed by the community outrage over the original high speed rail plan for Caltrain corridor in 2009, which was approved by voters a year before.

Some advocates often dismiss such concerns, but history shows that there were oppositions and concerns over wheelchair ramp for Muni Metro in San Francisco and higher platform for light rail in Downtown San Jose.

Many support the blended plan for high speed rail because they believe high speed rail would not force additional infrastructure onto the cities. If 50″ platform is an outcome because of high speed rail compatibility, that may be perceived as a violation of the blended plan.

Considering the cost and the impacts, there’s no good reason for Caltrain and high speed rail to justify having same platform height other than having more capacity and flexibility at Transbay Terminal.

If the problem is at Transbay Terminal, why not a solution at Transbay Terminal?

That’s one of the things that both Caltrain and high speed rail staff should look at and explain if they recommend a common platform height. Since the main reason for a common height is to enhance access to Transbay, there should be alternative solutions that are confined at Transbay. It would be unfair ask peninsula cities to adopt a platform height that they did not ask for if there’s a solution to address the problem at Transbay.

Unlike almost every other station, Transbay has unique circumstances that may make an on-site solution feasible that may not be feasible elsewhere:

  • It is a terminal stop – All passengers have to exit or board. There’s no dwell time issue like mid-line stops.
  • This station will likely be staffed at all hours.
  • Platform access may be limited to boarding and exiting. Passengers may wait in a separate area. This is already the case at 4th & King.
  • Modern trains should be able to spot at the same location along the platform with precision. Many rapid transit systems already do that.

Some of the potential solutions for Transbay to allow HSR/Caltrain compatibility without common platform height:

Mixed of low and high mini-platforms Platform with adjustable height Movable ramps
High platforms are further set back and use retractable ramp to connect with train. Low platforms are set closer to the train. Some platforms can still be dedicated to either HSR or Caltrain with fixed height. Platform that can adjust height. Some platforms can still be dedicated to either HSR or Caltrain with fixed height. Low platforms with movable ramps placed to connect with high speed train doors. Some platforms can still be dedicated to either HSR or Caltrain with fixed height.
Can serve all train doors? It can if it is designed well, since different trains have different door locations. Modern technology can provide consistent spotting so door is position to the ramp. Yes May not necessarily be all doors, but depending on boarding procedure not all doors would be available for boarding high speed trains.
Wheelchair and bike riders require assistance No. Ramp is deployed upon train arrival and be used by everyone. No. No. Ramp is deployed upon train arrival and be used by everyone.
Require labor to operate Yes Yes Yes
Challenge It is a new concept that requires more detailed design. A new concept. Need to test design whether it can withstand weight and provide reliable service. Requires planning.

Generally, our general thinking about rail platform is a fixed concrete structure that trains can slide to and doors can open along any part of the platform. We accepted this assumptions without question, yet many rail systems are installing devices like platform doors that require more precise spotting. If actually only a few feet per car along a long platform is used for loading, couldn’t the platform be designed in a way that can accommodate trains at two floor heights by shifting their spotting locations? We have to remember the goal is to provide unassisted and equal boarding for all riders for Caltrain and high speed rail, so other unconventional methods of platform sharing to should be given consideration.


If there’s a solution at Transbay, both operators can maintain their preferred height to maximize their operational needs. Cities would be relieved of not having to worry about high level platforms that don’t provide local benefits.

I think the worse outcome is some kind of a “force marriage” resulting in operational compromises. While I recognize that level boarding provides many benefits, these benefits don’t just exist between the train door and the platform, but also between the train door and the rest of the vehicle. Some of the ideas (onboard lift, bikes rolling up and down interior steps) simply defeat the purpose.

While some of the ideas at Transbay may require special designs, but even some of the ideas for common boarding height are also unconventional, whether it is movable steps, traps, onboard wheelchair lift, two sets of doors etc. I believe the maintenance cost and hassles would be far lower for any Transbay only solution (at most there are six platforms at Transbay to support, but actually two platforms need special treatments for operational flexibility). In comparison, any of the common platform height solution will affect hundreds of Caltrain vehicles if not all the other stations on the Caltrain line.


It is scary why some solutions were not even considered outright. So far the discussion is between engineers at Caltrain, high speed rail, and Transbay JPA. It seems like if two of the teams want the most simple engineering solution for themselves, they can bully the other team to accept a heavier burden of compatibility.

Engineering burden Separate platforms HSR using low platforms Caltrain using high platforms Transbay only solution
Caltrain X

If the burden is on Caltrain, it could potentially have the worse outcome since it affects operation and communities that will not be served by HSR. Caltrain should never bullied into accepting any burden until other feasible solutions are duly considered and not outright dismissed.

I am less concerned about two agencies adopting a common platform height, versus providing a seamless experience for Caltrain and high speed rail riders, particularly for disabled riders and riders with bicycles. If a common platform height means that some groups of riders will result in inferior access between platform to seat/wheelchair/storage area, I don’t think it is not worth the effort and expense (and I am not sure even whether it is ADA compliant). If an alternative on-site solution can allow platform sharing at Transbay, it would offer a more efficient train operation and better passenger experience with each agency accepting a platform height to best meet its needs.