Track Clearances at Passenger Platforms

[TTK]

I was provided with a sample track clearance diagram for an urban transit authority.

The project that I am working on does not necessarily have to follow these clearances, but I don't want to deviate from them unless absolutely necessary.

One of the clearance dimensions is a distance from the track side edge of the platform to the nearest structural column for the platform canopy. This is not measured from the track centerline so I don't believe the offset exists for the train. My best guess is that it has to do with some other preferred design constraint (such as passenger sight lines, etc..)

Now to my question....

Does anyone know why this offset constraint exists?

I believe the diagram required the structiral column to be a minimum of 8 ft from the edge of the platform (again, it was not related to the centerline of the track).

Thank you!

 

[civilperson]

Columns should not conflict with passenger waiting and loading space.

 

[NovusTechy]

Civilperson's answer to your query is correct.

The minimum single face platform width (UK is 2.5m) is to ensure that passengers do not stand on the edge of the platform if there are any non-stopping trains, there will always be a minimum dimension for whatever railway system.

The platform gauge (offset / height relative to the track) needs to be adequate for all trains using the route:-
- Structure clearance (train - platform edge KE clearance)
- Stepping distances (static train step - platform edge)
- Passing clearance (train - train KE clearance).

In the UK we have software which calculates this information for all trains using the route:-
- Kinematic envelope (considering the train characteristics)
- Platform stepping distances (static)
- Platform passing clearances
- Train - train passing clearances.