Rack & pinion railways (Cog railways)

[eMeS]

On normal railways, there's lots of safety features, and masses of experience & reports when things very occasionally go wrong.

On rack & pinion railways, matters are very different in that should the cog fail (metal fatigue etc.), I can't imagine that there's any braking possible from the wheels on the steep track. Has this happened?, or are the cogs and special track so heavily over-sized that it's impossible under normal use and replacement regimes? Are there other safety features which don't get a mention?

 

[Shimbleshanks]

I'd imagine that there are emergency braking systems that clamp onto the running rails in the event of overspeed or similar events. The only episode I can remember is the brake failure on the Snaefell Mountain Railway in the Isle of Man, but that uses the Fell system rather than rack.

 

[30907]

Depends on the railway. Rack-assisted railways generally have

This article https://en.m.wikipedia.org/wiki/Rack_railway

Apologies, something went wrong with the editing, see below

 

[eMeS]

Depends on the railway. Rack-assisted railways generally have

This article https://en.m.wikipedia.org/wiki/Rack_railway

Thanks for your pointer - I did check out the Wiki article before posting - it didn't seem to cover my concerns about failure modes. I guess cable cars are equally risky modes of transport, but there, the (a sample of) cable can be stress tested before catastrophe occurs.

 

[Shimbleshanks]

Thanks for your pointer - I did check out the Wiki article before posting - it didn't seem to cover my concerns about failure modes. I guess cable cars are equally risky modes of transport, but there, the (a sample of) cable can be stress tested before catastrophe occurs.

Again, there will be emergency brakes that clamp themselves to the rails in the event of the car exceeding a certain speed.

 

[30907]

Thanks for your pointer - I did check out the Wiki article before posting - it didn't seem to cover my concerns about failure modes. I guess cable cars are equally risky modes of transport, but there, the (a sample of) cable can be stress tested before catastrophe occurs.

Again, there will be emergency brakes that clamp themselves to the rails in the event of the car exceeding a certain speed.

The Wikipedia article on the Snowdon line (which had a serious accident on opening day) references this.

Back to my original post which suffered operator issues upthread

Rack railways fall into two types - pure rack, on which the loco/power car is always at the downhill end, and rack-and-adhesion (typically the longer Swiss routes), where trains are worked normally but non-powered vehicles are rack-equipped for additional safety.

Both also have all the other safety systems associated with rail, as appropriate to their speeds etc.

I would have thought that for rack-and-adhesion lines, with their less steep gradients, normal brakes would control a train even without the rack. A failure of the rack system would most likely cause it to jam solid or cause a (low-speed) derailment like a broken rail.

As mentioned by Shimbleshanks, rack-only lines can use additional track brakes.

 

[philthetube]

Normal brakes should contain the train but this cannot be relied on, slippery rails can greatly reduce braking efficiency, so on steel slopes something else is needed in case.

Windermere station was demolished a few years ago despite the driver doing everything correctly.