Compressed air systems

[zbang]

(splitting this from the SSR Resignalling thread)

Nov 30, 2020 18:43:04 GMT d7666 said:

Presumably though as long as pneumatic points are retained then the air main has to stay, which must be an aging liability asset ? Or is [was?] there a plan to go over to local compressors ? Apart from points and trainstops, and [?] V-frames [is that where their air comes from ?] there are no other devices the air main supplies are there ? Do depots have a compressed air supply off the air main for pneumatic tools, a lot of workshops in general [outside of railway] do use air.

Presumably every station with pneumatic points/stops/gates needs an air supply, as do inter-station interlockings (and IMRs and lever frames?). With mention of an "air main", was/is the air supplied by occasional compressors in the same manner as traction power? (Same locations?). I'd imagine this wouldn't be that difficult within the City, but going out to the 'burbs the stations are farther apart so I'd expect each station to have it's own air plant.

I don't recall anything about air systems in the books I've read. What supplies it (compressed, that is), from where, and what still uses it (public info only, please).

[MoreToJack]

The air main is, generally speaking, 'double-end fed' from the traction power substations, in line with much the rest of the network's various supplies.

I don't have any further information to hand on the equipment in use, but the air main is still a crucial part of the infrastructure on much of the network.

As you've suggested, pneumatic points, trainstops and ticket barriers all still require its provision, as do a number of remote IMRs and signal cabins converted to remote control operation.

[Deleted]

Not all Sub Stations supply the Air Main

They other dryers in the Sub Stations that dry the compressed air and its rated at 60psi this has a +- 3% tolerance. But with leaks etc usually its less then 60psi once it gets to the equipment.

Some areas are Single End Fed (one way) most though are Double End Fed (Both ways) where one Sub Station will feed towards another.

[zbang]

Thanks. Any ideas of consumption? I'd guess that each device averages only a fraction of a CFM but put the lot of them together plus system leakage and there's probably some serious compressors out there.

(Does the UK use cubic ft/minute or liters/minute?)

[class411]

Jan 7, 2021 21:48:35 GMT zbang said:

Thanks. Any ideas of consumption? I'd guess that each device averages only a fraction of a CFM but put the lot of them together plus system leakage and there's probably some serious compressors out there.

(Does the UK use cubic ft/minute or litres/minute?)

Generally, in any scientific or engineering context it's litres/min but there are probably a few instances of keeping old units ''cause that's how it's always been'.