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On 03/01/2020 at 21:34, rogerzilla said:

One of the quirks of driving from the trailer is that the vacuum brake can be applied, but not released.  Only the fireman can do that, from the footplate.  Therefore the driver has to be good at stopping in the right place at a platform, with only one shot at it, or needs a fireman alert enough to release the brake quickly if he's going to undershoot.

A couple of months ago we went through this myth on another thread. As soon as you release the brake by closing the brake valve you close up the vac system and the vac ejector on the loco,which operates continuously, restores the vac and releases the brake.  If this did not happen it would be impossible to  control the speed of the train on a down grade, every application would result in the train coming to a stop. On the other thread we sourced a photo of the brake valve in the driving trailer to prove the point that it was a normal vac brake valve as fitted on the engine.   

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Don't the push-pull locos have the usual large ejector/small ejector arrangement?  The small ejector runs continuously to compensate for leaks but it can't release the brakes - or will take an age to do so.

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2 hours ago, Phil Traxson said:

A couple of months ago we went through this myth on another thread. As soon as you release the brake by closing the brake valve you close up the vac system and the vac ejector on the loco,which operates continuously, restores the vac and releases the brake.  If this did not happen it would be impossible to  control the speed of the train on a down grade, every application would result in the train coming to a stop. On the other thread we sourced a photo of the brake valve in the driving trailer to prove the point that it was a normal vac brake valve as fitted on the engine.   

While this is true of the LMS engines and SR engines on GWR 14xx's are not fitted with a small ejector and your comment is incorrect. When you put the brake back to the running position, the vacuum pump will to some degree, depending on the speed you are going pull the brake off again, however generally below 15mph this will not work. The brake valve on the GWR auto trailers are different to the brake valve fitted on the engines. 

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For illustration here is the brake valve in the driving compartment GWR_coach_A38_225_driving_compartment.jp 

There is no ejector fitted with this is can only admit air to the train pipe. In pre preservation days the brake was released by the driver belling through to the fireman to blow the brake off. On the trailer we use on the SVR as we have a special grade of fireman who are passed out to be on the engine by themselves and to blow the brake off using their judgement (as does the SDR)

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Passed firemen, able to drive the loco if required, were always preferred for auto work, and failing that the most experienced men you could get.  You don't want a novice alone on the footplate of a loco for what was on any auto turn at least half of the running, and where the loco was 'sandwiched', all of it.  He has to maintain the boiler water level, fire, manage the reverser, and respond to the driver's bell signals, and while auto work is associated with bucolic branches, consider the lot of a Cathays fireman in the 50s on a Coryton service 4575 with a trailer being propelled and two being hauled having to keep the loco on top of the job on the 1 in 80 from Crwys to Heath Jc; you had to be well on top of your work and have your wits about you!

 

The brake valve in the trailer cab is a simple 'setter', similar in function to that in a guard's van but with a lever to effect finer control.  If the loco is using it's ejector to create vacuum, or it's small ejector to maintain it (54/64xx, 4575), then the driver in the trailer cab can admit air to the system to apply the brakes, which will then be released automatically as the loco's ejector blows them off.  If, however, the vacuum brake is applied on the loco, the driver in the trailer cab must use the bell signal to instruct the fireman to release if for him.  In such circumstances, the brake will not blow off when the trailer cab valve is closed until the fireman is instructed to release it on the loco.  

 

This is presumably what is meant by the suggestion that, once applied, an auto trains brakes cannot be released, which is of course not correct all the time, and while the train is running the driver in the trailer cab can used the valve to apply the brake and expect the brake to release when he closes the valve, giving him adequate control of the speed of the train using the vacuum brake.

 

In practice, the driver and fireman operated as a team, and most circumstances foresaw each other's requirement on regular jobs they knew well.  If you had a new mate, or were new to the job, extra care was taken to ensure you did what was expected of you at the right time; this is a feature of most steam age railway work.

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  • 6 months later...
On 01/01/2020 at 20:40, The Johnster said:

No 2721, 57xx, or 8750 panniers were ever fitted for auto working and neither were any 45xx small prairies.

 

Not sure that the 4575 'sloping tank' small prairies converted to auto work for the regular interval timetable being introduced in South Wales in 1953 count according to the OP's specification; they were certainly GW locos but this conversion, which only applied to selected members of the class, was carried out by BR.

 

Elsewhere on RMweb, I've read that at least one of the preserved 4575s was not auto-fitted by BR but has had the equipment fitted in preservation. Are the sloping tanks the only difference between the 45xx and 4575 classes because, if so, I take it a heritage railway could auto-fit one of the three preserved 45xx locos if desired?

 

On 03/01/2020 at 14:10, Steamport Southport said:

 

Linky for that.

 

http://www.gwr.org.uk/nopanniers.html

 

Jason

 

That page does say that "When more powerful autofitted engines were required in BR days the equipment was fitted to some 4500 class small prairie 2-6-2 locomotives." which doesn't tie up with what has been said on RMweb (ie. that only 4575s were fitted, not 4500/45xx with non-sloping tanks). Also, it doesn't say whether any members of the 1600 class were auto-fitted. It does say that 1600s replaced 850 and 2021 classes - given that many 2021s were auto-fitted according to that document, it would seem sensible to have fitted the 1600s. But were any of them auto-fitted?

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Simple (?) answers - only members of the 4575 class were auto fitted.  I know of no reason why members of the 4500 class could not be fitted but the 4575s had greater water capacity.  No 1600s were auto fitted.  They were busy enough on lightly laid sidings and branch lines.

 

Chris

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There would be nothing to prevent any owner of a preserved 45xx from fitting auto gear to it, or any other loco for that matter; all that is required is sufficient clearance underneath the loco for the auto linkage.  You could do it to Flying Scotsman if you really wanted to.  There is no reason that 45xx were not auto fitted for the South Wales 1953 regular interval timetable that saw some 4575s auto fitted, except that presumably the 45xx straight top tank version were lighter and hence more useful on route restricted lines.  Route restriction didn't matter in South Wales on the Valley network, where 'red' engines were allowed everywhere, so there was no reason to 'waste' lightweight 45xx that were needed on other work, and 4575 could be used; I also assume that there was a surplus of 4575s available for the work in 1953.  

 

The development of auto fitted locos on the GW is relevant to the choice of locos.  The original auto locos were redacted obsolete types that were nonetheless capable of taking over the job from steam railmotors which were victims of their own success in generating traffic and which struggled with trailers.  The railmotors were all rebuilt into auto trailers to join the already existing trailers that had originally been built to run with them.  The first locos built specifically for auto work were the 48xx, later to become the 14xx, a modernisation of the 517 class many of which had by that time been fitted with auto gear.  Like the 517s, the 48xx were considered to be passenger locos and had 5'2" driving wheels.  They were partnered by a non-fitted version, the 58xx, which were to perform light mixed traffic work on branches where auto trains were unsuitable for one reason or another.  

 

Next in the game were the 54xx 6-coupled panniers, again considered as a passenger loco and given 5'2" driving wheels.  Here the intention was to use the locos on a more suburban type of auto service where a little more power was needed to cope with 3 or 4 trailer trains.  They were not considered powerful enough for South Wales work, however, and as speed was not considered as important here the 64xx was developed with 4'7" driving wheels as an auto loco that could cope with the heavier loads as well as the gradients of the South Wales network, and again an non-auto version, the 74xx, was provided for light branch work in general, with the 4'7" drivers.  

 

The 45xx were originally developed as one of the Churchward standards for branch work, at a time before the railmotors had been superseded by auto-fitted locos, so they were never thought of as an auto type, and neither were the 4575 variants until 1953.  I suspect the 57xx and it's derivates were not considered fast enough for auto passenger work, and thus neither was the 94xx.  The 16xx were even slower, with 4'1" driving wheels, and in any case too valuable as unrestricted locos for route availability purposes. 

 

57xx hauled passenger trains of course, including auto trailers that they had to run around and haul back whence they came.  They hauled gangwayed stock between Newport and Brecon, a 2½ hour journey.  The 94xx also hauled passenger trains, including the Cheltenham-Gloucester part of Cheltenham-Paddington trains, which carried express headlamps.  16xx were used for branch passenger work in Scotland.  

 

The point I think I'm making in my roundabout way is that the GW, and thus the WR, had set ideas about which locos did what work, and the 0-6-0s and 0-4-2/2-4-0s had long histories of being associated with particular roles, new locos based on designs going back to the 1860s or further being introduced to replace older ones.  There is little real difference between a 517 and a 48xx, or a 2721 and a 57xx.  This small c conservative attitude mitigated against such new locos of a type not associated previously with auto work being kept off auto work while new locos of a type that were so associated were built in entire auto-fitted classes.  The only exception to this were the 4575 conversions.

 

In an ideal preservation scenario, the 'correct' way to restore a 4575 auto fitted loco is with auto gear in BR livery, 1953-6 plain black with unicycling lion, 1956 to withdrawal lined BR green with unicycling lion to '58, then ferret and dartboard.  If you want a previous BR or GW livery you should remove the auto gear.  Fitting auto gear to a loco that never carried it in BR service is 'incorrect', but if it's not my loco I can't do much more than comment about it!  

 

AFAIK all the auto fitted 4575s that were at Woodhams retained the auto gear, which is presumably the same gear as those locos preserved from that source still carry.

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Thanks for the quick replies.

 

On 11/07/2020 at 19:55, chrisf said:

Simple (?) answers - only members of the 4575 class were auto fitted.  I know of no reason why members of the 4500 class could not be fitted but the 4575s had greater water capacity.  No 1600s were auto fitted.  They were busy enough on lightly laid sidings and branch lines.

 

Chris

 

No auto-fitted 1600s, that makes justifying a purchase of Model Rail's new 1638 rather difficult again. For years I've thought, if anyone ever makes a decent RTR 16xx I'll have 1638 (assuming I'm remembering correctly that is the preserved one) in lined black (I've fancied a lined-black pannier for some time). Then I find out they never carried lined black so I thought ok, I won't have a 16xx after all. Now however I have started building a small layout (not the dream layout that I'm still designing) that doesn't have space for a run-round facility so autotrains would be useful and I thought that, had any of the 1600s been auto-fitted, could be an excuse to have 1638 in GWR green.

 

20 hours ago, The Johnster said:

There would be nothing to prevent any owner of a preserved 45xx from fitting auto gear to it, or any other loco for that matter; all that is required is sufficient clearance underneath the loco for the auto linkage.  You could do it to Flying Scotsman if you really wanted to.  There is no reason that 45xx were not auto fitted for the South Wales 1953 regular interval timetable that saw some 4575s auto fitted, except that presumably the 45xx straight top tank version were lighter and hence more useful on route restricted lines.  Route restriction didn't matter in South Wales on the Valley network, where 'red' engines were allowed everywhere, so there was no reason to 'waste' lightweight 45xx that were needed on other work, and 4575 could be used; I also assume that there was a surplus of 4575s available for the work in 1953.  

 

I imagine fitting Flying Scotsman would require bespoke linkages to be designed and built for it, which would be more expenive and complex (and thus a much-less realistic 'what if') than taking a set of auto-gear parts identical to that used on a 4575 and installing them using a identical procedure. I apply the "it's my railway/money so I'll run/collect what I like" rule but the "what I like" is in part defined by whether I can think up a plausable (to me) story for why said items are running. Sounds like a 45xx is similar enough to a 4575 that (if I ever manage to obtain one) I'll be happy with my 45xx pushing an autocoach so thanks for answering my query.

 

20 hours ago, The Johnster said:

The point I think I'm making in my roundabout way is that the GW, and thus the WR, had set ideas about which locos did what work, and the 0-6-0s and 0-4-2/2-4-0s had long histories of being associated with particular roles, new locos based on designs going back to the 1860s or further being introduced to replace older ones.  There is little real difference between a 517 and a 48xx, or a 2721 and a 57xx.  This small c conservative attitude mitigated against such new locos of a type not associated previously with auto work being kept off auto work while new locos of a type that were so associated were built in entire auto-fitted classes.  The only exception to this were the 4575 conversions.

In that regard, given my general very limited knowlege of steam loco types and that the 1600s were successors to the earlier auto-fitted 2021 class, I think I can forgive myself for thinking that 1600s may have been auto-fitted. I suppose the auto-fitted 6400s were also successors to 2021s. Anyway, I stand corrected now; no auto-fitted 1600s. That leaves me still looking for an auto-fitted 0-6-0; I suppose I could use a 6400 but unless I find one was used on the CardBach (as 1600s were) there isn't a second point of interest in the class.

 

The only other preserved types I can think of that I haven't already discounted (or confirmed as not having been auto-fitted) are the outside-cylinder 1366 class panniers and 1361 saddle tanks. Given that what I've read about these types suggests they were designed as shunting engines I very much doubt they were auto-fitted, but I cannot find anything that states outright that they weren't. I also found this history of 1369 which twice mentions auto-coaches. Of course they probably just ran round the coach at each end of the journey but it did give me a very faint hope that 1369 has been auto-fitted at some point. Can anyone confirm that 1366/1361 weren't auto-fitted as I assume?

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There's certainly no record in RCTS of the 136x or 16xx being autofitted. There was probably no need for the 16s to have the gear, with the 54s and 64s replacing  autofitted 2021s on those duties. Only a small minority of the 2021s were ever autofitted. Interestingly the autogear seems to have been regularly swapped on and off pre group classes, and all sorts of locos were fitted from time to time, including small numbers of 4'7 wheel tanks - mostly though the earliest and least powerful. 

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The 16xx is not really a modernised 2021; that would be the 54/64/74xx; the 16xx were a modern replacement for the 833 class if anything.  

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On 12/07/2020 at 01:03, The Johnster said:

There would be nothing to prevent any owner of a preserved 45xx from fitting auto gear to it, or any other loco for that matter; all that is required is sufficient clearance underneath the loco for the auto linkage. 

 

AFAIK all the auto fitted 4575s that were at Woodhams retained the auto gear, which is presumably the same gear as those locos preserved from that source still carry.

5572 was the only auto-fitted 4575 to come out of Woodham's yard and is preserved at GWS Didcot.  Although it has not run in many years and is painted in Great Western livery it does appear to be still carrying its B.R. fitted auto-gear.  5526 was fitted with auto-gear at the SDR Buckfastleigh but it may have subsequently been removed,

Ray.

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In which case 5572 is either carrying an incorrect livery or incorrect auto gear depending on which way you look at it.  The auto gear was fitted to the next 4575s going through works in 1953, which is why the numbers appear random. 
 

The gear is entirely mechanical and, properly greased, should not deteriorate though it probably needs freeing up after a long period of disuse.  

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13 hours ago, The Johnster said:

The 16xx is not really a modernised 2021; that would be the 54/64/74xx; the 16xx were a modern replacement for the 833 class if anything.  

 

Not at all sure I can agree with you. Wasn't 833 a 517? Do you mean the 850s?

The 2021s were basically an 850/1901 with a longer firebox and wheelbase, so they were very similar. The 2021s U class boiler was of similar dimensions to the Std 16 on the 16s, whereas the Std 21 on the 54/64/74 was significantly larger.  And the 16s had the same 4'1.5 wheels as the 2021s. 


There were 158 850s/1901s and 140 2021s, so I submit that 115 54/64/74s weren't enough to replace them. If you add 80 16s the numbers start looking more reasonable.  I submit that the 54/64 was a replacement for all the pre group autofitted 0-6-0s of various classes, the 74s were a replacement for all pre group types lighter than the 57s, which again wasn't just 2021s but a mix of 4'7.5 and 4'1.5 wheel types, and the 16s were a replacement for the rest of the small types. We shouldn't forget that the route mileage of lighter coloured routes was decreasing with upgrades and closures, especially during /after the war.

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