Date: 2024-11-30 03:22 pm (UTC)
toothycat: (Default)
From: [personal profile] toothycat
Driverless trains aside, signal passed at danger should not be a thing that is possible. We've had the tech for decades. It is 2024. Trains should brake automatically when passing a red light. Tech isn't complicated, and can be retrofitted. Other countries do this.

signal passed at danger

Date: 2024-11-30 05:23 pm (UTC)
bens_dad: (Default)
From: [personal profile] bens_dad
signal passed at danger should not be a thing that is possible

If the train brakes automatically when it passes the red light, that is a SPAD, but should not be a problem, as long as the brakes stop the train.

This term covers equipment fitted to trains and on the track that reduces the consequences of a train passing a signal at danger, by automatically applying the train's brakes. These systems do not prevent SPADs, but they do reduce the risks posed by SPADs.
The train protection and warning system (TPWS) has been installed across the network and is successfully reducing SPAD risk.
There have been a number of potential collisions prevented by TPWS.

https://www.orr.gov.uk/guidance-compliance/rail/health-safety/infrastructure/signals-passed-danger

Re: signal passed at danger

Date: 2024-11-30 05:37 pm (UTC)
toothycat: (Default)
From: [personal profile] toothycat
...I did not know that. Thanks! I'd been thinking e.g. of the Salisbury crash, but reading up on it now, the driver and the automation both applied brakes, and the train failed to stop in time despite this.

Date: 2024-11-30 05:54 pm (UTC)
armiphlage: Ukraine (Default)
From: [personal profile] armiphlage
Tripcocks have been around since the 19th century. When a signal light turns red, a motor raises a metal bar. If a train passes, the bar hits a brake lever on the train bogies to activate the emergency brakes.

It doesn't always work, as the metal bar has to be aligned with the brake lever on the train. Wear on rails, wheels, and levers contributed to a crash in 1995 in Toronto; the bar hit a bolt on the train instead of the brake lever.

https://en.wikipedia.org/wiki/Train_stop
https://en.wikipedia.org/wiki/1995_Russell_Hill_subway_accident

4

Date: 2024-12-02 11:55 am (UTC)
danieldwilliam: (Default)
From: [personal profile] danieldwilliam
If driverless trains very very expensive because you need to change lots of other things to make them work that implies that the cost-benefit calculation might be more favourable if you already had to replace all the rolling stock on a line. Which is a once in a 50 (?) year event for each line. Certainly decades.

During which time there will improvements in automation and other changes to how things work.

Seems like a wait and see approach is the right one.

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