GWR 7100 Class

[LNWR18901910]

After the success of my LNWR Mogul, I have planned a project for quite some time. It's the GWR 7100 Class 2-6-4T.

 

The  61xx Large Prairies are quite interesting and so have the GWR 72xx 2-8-2T tank engines. The 72xx did strike as a 2-6-4T which the LMS mostly used when it pulled coaches. This would be another 'what-if' locomotive that I have always wanted to do, really.

 

The GWR 7100 Class were designed and built with incorporated plans of the 61xx 2-6-2T and 72xx 2-8-2T locomotives but with a double-trailing rear-axle. The class earned the nickname 'Platypuses' because of the rear double trailing axles like tails. 100 of these were built between 1933 to 1935 and were used on rural and suburban branchlines. The class survived into British Railways nationalisation until they were withdrawn between 1961 and 1964, one year before steam on the British Railways Western Region ended. No less than six locomotives survive under preservation including the first of its class which was first built at Wolverhampton and still survives today.

 

I haven't any pictures, but when I do get around to it, you'll all see the locomotive taking shape as it gradually builds it way up.

[chrisf]

This is indeed an interesting might-have-been.  I do not know why the GWR never tried 2-6-4Ts.  It may have been put off by the 12 0-6-4Ts that it inherited from the Barry Railway.  They were rather prone to derailment when running bunker first and one example overturned.  Despite being only 12 years old they were all withdrawn in 1926.

 

Chris

[Miss Prism]

100 of these were built between 1933 to 1935 and were used on rural and suburban branchlines.

 

A 90ton redroute loco on rural branchlines?

[JimC]

This is indeed an interesting might-have-been.  I do not know why the GWR never tried 2-6-4Ts. 

The 51s et al carried 2,000 gallons of water, as much as the BR 2-6-4Ts. So a 7200 style extended bunker on a 5101 or 3150 would probably give around 2,700 gallons of water, enough for quite considerable trips, so you'd be looking at  doing long cross country routes. Are you planning the Standard 2 boiler like the 61s, or the larger diameter Standard 4 like the 72s and the 3150s?

[LNWR18901910]

 

A 90ton redroute loco on rural branchlines?

 

Yes, my good woman. Why not? Of course, that can happen.

[LNWR18901910]

The 51s et al carried 2,000 gallons of water, as much as the BR 2-6-4Ts. So a 7200 style extended bunker on a 5101 or 3150 would probably give around 2,700 gallons of water, enough for quite considerable trips, so you'd be looking at  doing long cross country routes. Are you planning the Standard 2 boiler like the 61s, or the larger diameter Standard 4 like the 72s and the 3150s?

Good question, Sir. I have two Hornby and Airfix 61xx Large Prairie bodies and the back of one of them is cut away and the other would have its bunker cutt off and grafted into its place. A double trailing bogie would also be fitted on underneath.

[TheSignalEngineer]

 

A 90 ton red route loco on rural branch lines?

 

Stanier, Fairburn and 80xxx  would have qualified as Blue. The Fowler 2-6-4T was a bit heavy on the crank axle so would have been Red.

 

There's a couple of good documents available here http://www.michaelclemensrailways.co.uk/?atk=634

 

The first is a GWR Engine Route Map from 1931, hand amended up to 1957. The second gives route availability colours for GWR classes, BR Standards, Diesels, DMUs and Shunters on Lines transferred to the LMR and lines in the Gloucester District. It also gives local restrictions and engines authorised on former LMS lines operated by the Gloucester District.

[Miss Prism]

Excellent GWR Engine Route Map. I've added a link to it from gwr.org. Thanks.

Edited November 21, 2017 by Miss Prism

[LNWR18901910]

Excellent GWR Engine Route Map. I've added a link to it from gwr.org. Thanks.

I'm terribly sorry, but I don't see any link whatsoever.

[Miss Prism]

I'm terribly sorry, but I don't see any link whatsoever.

 

The link is on the links page.

[LNWR18901910]

The link is on the links page.

Thank you kindly for pointing that out. I have followed it.

[DCB]

The 2-6-4T could well have been rebuilt from the 3150 class instead of the 31XX 2-6-2Ts of 1938.   Both 3150 and 31XX  had the same Std 4 boiler as the 42XX and 72XX 2-8-0 and 2-8-2 tanks and were an accountancy wangle which would have worked equally well for a longer range tank instead of a more powerful smaller wheeled banker.  I is believed the 31XX were worse as bankers than the 3150 as with higher boiler pressure and smaller wheels they were more prone to slipping.   However they were very successful suburban passenger locos, doing exactly the same sort of work the 2-6-4 T might have done.   The 31XX and 3150 are among the few GWR locos not available RTR in 00 nor do I know of a kit so why not build one of those instead of a 2-6-4T.   I have a 3150 planned based on a Grafar 00 81XX.

I don't really know what use a 2-6-4T would have been compared to the 2-6-2T unless it had the Std 1 firebox on a Std 4 boiler barrel, something which Swindon could have built from standard parts   The LMS 2-6-4s had longer fireboxes than GW locos which pushed the cabs back on the frames and necessitated the trailing truck rather than extra coal  and water capacity while the LMS Tanks ended at the cab spectacle plate I believe whereas the GW ones continued to the cab doorway and both were nominally 2000 gallon capacity.  There is little doubt the LMS 2-6-4Ts and BR Std versions were excellent suburban passenger locos but so were the GW Prairies.  Sadly no other UK railway managed to make a decent passenger 2-6-4T  The southern's Rivers couldn't stay on the track and W1s had no turn of speed, while the LNER L1 seemed to be unable to stay together at high speed and L2 and L3 were goods locos.  Maybe if the L1s had had 3 cylinders with inside stephenson's valve gear NER style they would have been on to a winner.

Edited November 22, 2017 by DavidCBroad

[LNWR18901910]

The 2-6-4T could well have been rebuilt from the 3150 class instead of the 31XX 2-6-2Ts of 1938.   Both 3150 and 31XX  had the same Std 4 boiler as the 42XX and 72XX 2-8-0 and 2-8-2 tanks and were an accountancy wangle which would have worked equally well for a longer range tank instead of a more powerful smaller wheeled banker.  I is believed the 31XX were worse as bankers than the 3150 as with higher boiler pressure and smaller wheels they were more prone to slipping.   However they were very successful suburban passenger locos, doing exactly the same sort of work the 2-6-4 T might have done.   The 31XX and 3150 are among the few GWR locos not available RTR in 00 nor do I know of a kit so why not build one of those instead of a 2-6-4T.   I have a 3150 planned based on a Grafar 00 81XX.

I don't really know what use a 2-6-4T would have been compared to the 2-6-2T unless it had the Std 1 firebox on a Std 4 boiler barrel, something which Swindon could have built from standard parts   The LMS 2-6-4s had longer fireboxes than GW locos which pushed the cabs back on the frames and necessitated the trailing truck rather than extra coal  and water capacity while the LMS Tanks ended at the cab spectacle plate I believe whereas the GW ones continued to the cab doorway and both were nominally 2000 gallon capacity.  There is little doubt the LMS 2-6-4Ts and BR Std versions were excellent suburban passenger locos but so were the GW Prairies.  Sadly no other UK railway managed to make a decent passenger 2-6-4T  The southern's Rivers couldn't stay on the track and W1s had no turn of speed, while the LNER L1 seemed to be unable to stay together at high speed and L2 and L3 were goods locos.  Maybe if the L1s had had 3 cylinders with inside stephenson's valve gear NER style they would have been on to a winner.

Thanks for sharing that. Very interesting points on 2-6-4T tank locomotives.

[unravelled]

Building aGW 2-6-4 has been one of my plans for a while. My thought  was that  it would be done for an increased coal load, rather that extra water, which is more conveniently replenished. So  what was the range of a 2-6-2 on a normal servive  and coal load, and what improvement would a 2-6-4 give? One thought of mine was that they could be useful on a Paddington Worcester semi fast.

 

Looking forward to progress here

 

Dave

[JimC]

Building a GW 2-6-4 has been one of my plans for a while. My thought  was that  it would be done for an increased coal load... 

 

The coal capacity on the large prairies was 4 tons, as against 4.25 tons on Collett 3,000 gallon tenders. Like most larger GWR tank engines there was a water tank under the coal - look for the diagonal line of close spaced rivets on the bunker.

So a 2-6-4 could have the same the same coal capacity as a small tender engine plus approaching the same amount of water.

I agree the Std 4 boiler would be a more likely option. I suppose a Dapol City of Truro could donate one, although time has not been kind to the quality of the mouldings.

 

An amusing option for a fictional large GWR tank engine would be a 4-6-2T based around the Manor chassis and boiler.

[LNWR18901910]

Building aGW 2-6-4 has been one of my plans for a while. My thought  was that  it would be done for an increased coal load, rather that extra water, which is more conveniently replenished. So  what was the range of a 2-6-2 on a normal servive  and coal load, and what improvement would a 2-6-4 give? One thought of mine was that they could be useful on a Paddington Worcester semi fast.

 

Looking forward to progress here

 

Dave

Thanks, Dave. I am making good progress on it so far. It's slowly starting to take shape.

[LNWR18901910]

And here it is after so long!

 

 

Finally, after so long, my GWR 71xx Platypus is finally taking shape! Once the body is finished, the chassis, on the other hand, is a different matter.

[tomparryharry]

Didn't Wrenn turn out a 2-6-4? Called an 8100.....

 

Cheers,

 

Ian.

[LNWR18901910]

Didn't Wrenn turn out a 2-6-4? Called an 8100.....

 

Cheers,

 

Ian.

That was a repaint of a BR Standard 4MT 2-6-4T.