Have enough handles in Quorn, plus my own thanx
I wasn't aware you had an 830 and a 930 up there
I realise the W is not a SA/NT loco, but then again could the class be as PRR's W933,934 have done more time in S.A. than they ever did in W.A!!
Reason I ask abou W is there have been a large variety of air brake systems used on these loco's.
The first W's to get air brake were the ST W(22-25) which had complete No. 4 brake systems
Next were PRR W933,934 which initially maintained vacuum as an independent brake on the engine unit itself, but maintained the train pipe at front of engine unit and through pipe, through the tender. Air was installed, the automatic portion of A6ET which operated on the tender only, and obviously had a train pipe front and back. Later the vacuum was removed and an independent portion was added, giving full A6ET system
When the wolf in sheeps clothing, W916 was changed into ST look alike W22, in lieu of No. 4 (which would have been historically correct) W22 was fitted out with A7EL, which essentially behaves the same as A6ET anyway. Although fitted with A7EL brake valves, W22 does not have No.3 and 4 Independant Release and Control Pipes fitted (yet)
W901 at Steamtown Peterborough again has a hybrid arrangement, initially fitted the same as PRR's W933,934 retaining vacuum and the automatic portion of A6ET. Later vacuum was removed but instead of going full A6ET with independent valve and distributing valve, W901 used the straight air independent valve from a No.4 system, thereby utilising a double check valve. Advantages; has independent brake with A6ET automatic valve giving min reduction applications, but disadvanteged over full A6ET in that straight air can't be released by the independent valve, it can only be released by release valve
As you can see I have a bit of a fascination here with W class loco's brake systems, so still wondering how is W924 set up??