9f loco injector pipework

[mswjr]

I am building a gauge one model of a 9 f, I have just bought some castings for the injector pipework, So whist looking at pictures of the full size loco, I have noticed that some locos have a big large diameter pipe amongst the injector pipework and some have not this large pipe, so can i ask does anyone know what this pipe is and why have some got it and some not,, I have looked at 9 fs for ages on the web, and can not get the answer.

 Thankyou  Garry

[jim.snowdon]

I would suggest that it is the steam feed pipe to the exhaust steam injector, where the loco is  fitted with one. Because exhaust steam injectors work best under sustained steady state conditions, it is quite likely that for locomotives that were going to be on duties with a lot of stops and time spent in loops, it would have made more sense to have them fitted with two live steam injectors instead of 1 X live plus 1 X exhaust.

 

Jim

[LMS2968]

As Jim says. The exhaust steam injector was not reliable. There was a toggle valve to switch between and exhaust steam operation and this was, er, delicate. One answer was to blank off the exhaust steam supply and, in some cases, remove the supply pipe. I would suggest that all 9Fs had the supply pipe as built.

[mswjr]

Thankyou for that Gents, That makes sense as i have seen the large dia pipe, (exhaust inj) on some ,so maybe it was removed on others , I understand now, so ill have to find a good picture of the one that im doing, Thankyou

[john new]

I also noticed from my own photos that this pipework varies on the two surviving Britannias. That on 70000 in preservation differs from 70013's. Photos not currently to hand but I spotted the difference a year or two back after seeing them both at Weymouth.

[jim.snowdon]

51 minutes ago, john new said:

I also noticed from my own photos that this pipework varies on the two surviving Britannias. That on 70000 in preservation differs from 70013's. Photos not currently to hand but I spotted the difference a year or two back after seeing them both at Weymouth.

Just as BR modified locomotives to suit circumstances, locomotives in preservation are not always as they came out of service either, due to the needs of operation in a different railway environment as well as the differing availability of spare/replacement components.

 

Jim