Express speeds for the GWR 28xx and 2884 classes?

[Dunsignalling]

May be not far off the verbatim! And, as a patriotic one-off, probably justifiable. In everyday service, probably not!

Just as well they didn't have to obey the rules set for World Land Speed Records - they would have had to do it again in the opposite direction within an hour! 

 

John

[34theletterbetweenB&D]

When I was an apprentice I worked on a lathe with a six feet diameter faceplate. The lathe had a top speed of 250RPM and I soon became aware how violent it could be if the job bolted to the face plate was the slightest bit out of balance.

 

I read somewhere that 250RPM was a sensible rotation speed for a steam locomotive but cannot prove this. My gut feeling is that to run at any wheel speed faster than 250RPM the locomotive needs to be well balanced and in good condition...

 

The typically worn state of an in service heavy freight unit would be enough to put off most crews from overmuch speed. Better maintained big wheel express units could give their crews a hard time when nearing works overhaul. I remember reading one striking account of a night run where the signal lights were only visible as blurred streaks whenever the loco was really opened out, and the fireman was having trouble reliably getting the shovel blade cleanly through the firehole door. (On the other hand the resulting 'agitation' of the grate did - he felt - really assist in the free steaming: no trouble whatsoever in power production, so it wasn't all downside!)

[The Stationmaster]

The typically worn state of an in service heavy freight unit would be enough to put off most crews from overmuch speed. Better maintained big wheel express units could give their crews a hard time when nearing works overhaul. I remember reading one striking account of a night run where the signal lights were only visible as blurred streaks whenever the loco was really opened out, and the fireman was having trouble reliably getting the shovel blade cleanly through the firehole door. (On the other hand the resulting 'agitation' of the grate did - he felt - really assist in the free steaming: no trouble whatsoever in power production, so it wasn't all downside!)

Hang on a minute - this thread is about Western engines

[PhilH]

Hang on a minute - this thread is about Western engines

 

I had the good fortune (?) to have a trip on the footplate of one of them things on the SVR at the weekend.....just about proved every point made in this thread!

[OnTheBranchline]

Are there any pictures to be found of 28xx and 2884 class engines pulling expresses in GWR days?

 

I know there's one in a Taunton article in the GWRJ magazine. Other than that, I haven't seen any.

[The Johnster]

Not sure about GWR days but certainly in the 50s on the Bank Holiday weekend West Country trains.  IIRC 4'7" wheeled locos were expected to keep timings based on 50mph running.

[Dunsignalling]

60MPH top speed for a 28xx then?

In extremis, possibly, but more like 45-50 as a general rule, I would think.  

 

John

[Dunsignalling]

It ran the middle big end (not exactly a rare event on an A4 of course.

 

9Fs were indeed recorded at c.90mph and reputedly rode well at that speed although various parts of their anatomy were definitely in 'whirling dervish' mode at that speed, hence their being banned from passenger train use on the ECML.

I was told by a couple of drivers that whilst 9Fs in good nick would have had little difficulty in approaching/attaining 90mph if required, most that did were never quite the same afterwards. I gather they would willingly belt along all day at 70-75, though.

 

John

Edited December 3, 2017 by Dunsignalling

[Dunsignalling]

Not sure about GWR days but certainly in the 50s on the Bank Holiday weekend West Country trains.  IIRC 4'7" wheeled locos were expected to keep timings based on 50mph running.

From what I remember of Summer Saturdays in the West Country, 50mph was generally something only to be dreamed of whatever size wheels the loco had.

Edited December 3, 2017 by Dunsignalling

[TheSignalEngineer]

From what I remember of Summer Saturdays in the West Country, 50mph was generally something only to be dreamed of whatever size wheels the loco had.

Not unusual to take an hour or more from Temple Meads to where Bristol Parkway is now.

There were instances of 28xx working stock shuffles on summer Saturdays to move stock back after unbalanced workings but when you consider that WD 2-8-0s were limited to 50mph on the WR I doubt that they would be doing much more than that.

[The Stationmaster]

Not unusual to take an hour or more from Temple Meads to where Bristol Parkway is now.

There were instances of 28xx working stock shuffles on summer Saturdays to move stock back after unbalanced workings but when you consider that WD 2-8-0s were limited to 50mph on the WR I doubt that they would be doing much more than that.

 

I can't find any passenger loads or speeds for 28Xx but as 47XX were officially limited to 60 mph on passenger trains I would agree that no more than 50mph is a fair estimate for a 28XX (on a good day  )

[The Johnster]

From what I remember of Summer Saturdays in the West Country, 50mph was generally something only to be dreamed of whatever size wheels the loco had.

 

Good point!  IIRC the 56xx, same size driving wheels, were limited to 50mph.

[The Stationmaster]

Good point!  IIRC the 56xx, same size driving wheels, were limited to 50mph.

 

Interesting - when did that come in as they certainly weren't shown as restricted in the 1963 loads book?  (in fact none of the GW design tank engines were shown as limited - the only engines considered as mixed traffic to which limits applied were the 47XX and the 9Fs.  No passenger loads were shown for the 28XX hence no limit but practicality was another thing of course)

[ThePipersSon]

Just a thought - were they fitted with speedometers? - without them, any speed limit would be speculative - just as fast as the drivers risked taking them.

[Reorte]

Just a thought - were they fitted with speedometers? - without them, any speed limit would be speculative - just as fast as the drivers risked taking them.

Someone may have timed the mileposts.

[The Stationmaster]

Just a thought - were they fitted with speedometers? - without them, any speed limit would be speculative - just as fast as the drivers risked taking them.

 

I recall somewhere seeing something about calculating speeds (in an official document that is).  But that would be irrelevant as far as Drivers were concerned as they had no means of timing anything because they weren't issued with watches and in any case were meant to be watching signals, not mileposts or telegraph poles.  The simple answer was no doubt 'if it feels alright then it is alright' on non-speedometer equipped engines, i.e. the vast majority of engines.

[New Haven Neil]

The 93mph 9F was of course timed by Gerry Fiennes - who was on the train, and just happened to be the General Manager of the Eastern region at the time.  See 'I Tried to Run a Railway'.

 

The limiting factor is piston speed, tempered by the ability of the cylinder/valve/gear design to breathe as mentioned previously, and the balance issues.  Exceeding a certain piston speed will cause ring damage, which might explain 'it was never the same afterwards' comments.  See how GW locos have a long piston stroke = high piston speeds, whereas Mr Bullied preferred a shorter stroke, and his locos with modest size wheels were often timed over 100 mph and the bits didn't fall off.  Whilst Mike's GW locos could make power for sure, they weren't the fleetest of foot in comparison with some others.  The long stroke did give them that ability to start so well, a feature that served many GW classes well, which others could not emulate.

 

A 28? Well, yeah, I'd say 45 - 50 would be about all the crew could stand, and the loco too, for any time.  It may reach 60 at a real push, but it nor the crew would be happy in the slightest!

Edited December 5, 2017 by New Haven Neil

[JimC]

I can't find any passenger loads or speeds for 28Xx but as 47XX were officially limited to 60 mph on passenger trains I would agree that no more than 50mph is a fair estimate for a 28XX (on a good day  )

The 47s were limited to 60mph because they tended to "nose about" above that speed, Cook says, and he puts it down to the extra sideplay and inclined planes on the rear axle. The 28s didn't have that arrangement, having a shorter fixed wheelbase, so there's no reason to suppose they had a proportional limit.

[The Stationmaster]

The 47s were limited to 60mph because they tended to "nose about" above that speed, Cook says, and he puts it down to the extra sideplay and inclined planes on the rear axle. The 28s didn't have that arrangement, having a shorter fixed wheelbase, so there's no reason to suppose they had a proportional limit.

 

No reason at all to assume such - but plenty of reason to think about them in the way described by New Haven Neil