Would platform screen doors ever work on the Thameslink Core?

[Bletchleyite]

Presumably there is a direct mechanical interlocking on lift doors between the lift car and the doors. That isn't really possible with a moving train and it has to be done with electronic means.

Indeed. With lifts, the carriage's doors have a protruding piece of metal which engages in a piece of metal on the floor's doors and causes them to open and close/lock together - they don't have their own mechanism.

 

[Bald Rick]

What material difference would make doors that only open when a train is there impossible while doors that only open when a lift is there have been successfully employed all over the world for over a century?

Somehow you quoted @swt_passenger when quoting me, so I’ll reply..

The obvious material difference is that in a typical lift environment, the same lift stops at any given door. In the rail environment you can have scores / hundreds of different trains, each with (potentially) a different driver, driving style, and possibly different characteristics. And, typically, the trains need to be capable of opening with and without platform edge doors being present. Other factors:

1) the need to be able to command the doors in automatic and manual mode
2) trains passing at up to 60mph, with all the attendant aerodynamic flows
3) all doors need to be opening / closing at (nearly) the same time, and same speed.
4) the necessary lateral gap between platform door and train door
5) the need to interlock platform doors to the train control system

And so on.

 

[Dent]

Somehow you quoted @swt_passenger when quoting me, so I’ll reply..

The obvious material difference is that in a typical lift environment, the same lift stops at any given door. In the rail environment you can have scores / hundreds of different trains, each with (potentially) a different driver, driving style, and possibly different characteristics. And, typically, the trains need to be capable of opening with and without platform edge doors being present. Other factors:

1) the need to be able to command the doors in automatic and manual mode
2) trains passing at up to 60mph, with all the attendant aerodynamic flows
3) all doors need to be opening / closing at (nearly) the same time, and same speed.
4) the necessary lateral gap between platform door and train door
5) the need to interlock platform doors to the train control system

And so on.

Are any of these issues really insurmountable? Most of them are not even issues, or relevant to selective door opening.

 

[Bald Rick]

Are any of these issues really insurmountable? Most of them are not even issues, or relevant to selective door opening.

Insurmountable, no. But not cheap or easy. At least that’s what the engineers on Crossrail told me a few years ago. It’s a complex system.

 

[pdeaves]

What material difference would make doors that only open when a train is there impossible while doors that only open when a lift is there have been successfully employed all over the world for over a century?

For one thing, I know of no lift system where different sized lifts may turn up.

 

[JaJaWa]

DB uses an interesting variant on platforms where 200km/h+ trains pass through non-stop, which wasn't previously allowed but was introduced for the WCML-PUG1-like upgrade of the Hamburg-Berlin route. They have fences on the platform but they are a metre or so back from the edge, and you're meant to stay on the "safe" side of them until your train stops. Because they're back from the train they don't need to match door positions. Something like this could work on Manchester Piccadilly P13/14, say.

China Railway Highspeed does this with actual PEDs

 

[Dent]

For one thing, I know of no lift system where different sized lifts may turn up.

Irrelevant. Each door needs to open if that door is lined up with a train, and not if it isn't. This is no different to a lift landing door opening if that door is lined up with a lift and not if it isn't. The doors on the train are all the same size anyway, not that that is relevant.

 

[gordonthemoron]

why not half height barriers/doors, like they have in Bangkok & Taipei?

 

[JKF]

why not half height barriers/doors, like they have in Bangkok & Taipei?

I presume one of the chief advantages of full height platform edge doors is the prevention of suicides. Half height barriers won’t do this.