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Post by twihlet on Aug 30, 2015 18:57:41 GMT
The A class steam locos were designed and built as mass rapid transit prime-movers. Later in life they took trains out to the newly built suburbs. I would like to know the sort of speeds that these trains achieved when in the great outdoors between Wembley and Harrow, for example. I cannot find any gen from published sources, or even old timetables which would give me a clue. I'm guessing they cruised at 40 with the odd spurt higher when the gradient and winds were favourable, but is there any evidence??
Anyone with an 1890 timetable out there?
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roythebus
Pleased to say the restoration of BEA coach MLL738 is as complete as it can be, now restoring MLL721
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Post by roythebus on Sept 4, 2015 19:37:13 GMT
I can't suggest a definitive answer, but judging from my experience on heritage railways with small steam locos (O2, Terrier etc) similar size to the Met locos, whilst any of these could in theory run at 40 mph+, they certainly wouldn't "cruise" at that speed.
The Terriers on the Isle of Wight (limited to 25 by light railway order) easily get to 25 with a 6 car set of Victorian coaches, probably a similar weight to the typical Met train of that era; the O2 last weekend on a members special got to 35 with a 4 car bogie set. The O2's when in service were reportedly capable of getting to 60 on the island, especially downhill, but there stations were quite far apart.
The Terriers on the K&ESR can get to 30+ with a limited load of 2 BR Mk1 coaches or 6 Victorian 4 wheelers; they are limited to what they can haul by Rolvenden Bank!
Therefore I'd suggest the Met a class would probably do about 25 between station, much the same speed as trains today!
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Post by stapler on Sept 6, 2015 10:05:56 GMT
Cecil J Allen said that in Edwardian times, the speed of GER J69s on Chingfords was "nearer to 60 than 50" across the Marshes. Surely the determining factors would have been distance between stations, gradient, and signalling? I can't imagine an A class exceeding 25 save out in the far reaches of the Met...
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roythebus
Pleased to say the restoration of BEA coach MLL738 is as complete as it can be, now restoring MLL721
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Post by roythebus on Sept 9, 2015 7:53:17 GMT
My thoughts entirely. Even the modern electric stock has difficulty doing much more than 30 in tunnel sections.
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Post by shunterl44 on Sept 9, 2015 8:42:46 GMT
Comparing Met 1 with a Terrier is a bit like comparing a race horse with a cart horse. Met 1 has 66" (1.524m) driving wheels while those of a Terrier are only 48" (1.219m) Also Met 1 has a tractive effort of 14515 lbs against only 7650 lbs for a Terrier.
I have driven Met 1 from Harrow-on-the-Hill to Amersham for Steam on the Met in the 90s and while I don't have a record of the top speed, I recall it being in the 50s.
The Met engines were designed for rapid acceleration in the tunnel sections the first worked in and this gave them big driving wheels. A by product of this is a good top speed; think of the Sterling Singles on the GNR and some of the GWR's early locomotives.
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Post by norbitonflyer on Sept 9, 2015 12:51:24 GMT
Whilst big driving wheels do make for a good top speed, acceleration depends on tractive effort, which (all other things, notably cylinder dimensions and boiler pressures, being equal) is inversely proportional to the driving wheel diameter. (Essentially a steam locomotive has a single-speed transmission, an 8-foot Stirling Single is always in top gear, a 9F with its relatively tiny wheels always in bottom gear). Or to look at it another way - each stroke of the cylinder has to carry the locomotive a distance equal to the circumference of the wheel - the bigger the wheels, the more work each stroke of the cylinder has to do. At high speeds small wheels are a hindrance, because the pistons have to move faster. The extremes of the early days, with driving wheels towering over the footplate crew, were moderated in later years by improvements in materials, allowing pistons to move faster, and by ever increasing train weights: this not only required greater starting tractive effort (although banking out of places like Euston continued until very late, and was not just a convenient way of getting the ECS loco out of the platform) but more than one pair of driving wheels to get sufficient traction - and there was a limit to how long coupling rods could be made.
Thus the Met A class's has higher tractive effort than a Terrier despite, not because of, its larger wheels. (Mainly because it had 17 inch diameter cylinders, and the Terrier only had 12 inch ones)
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Post by bassmike on Sept 9, 2015 16:51:31 GMT
Talking about speeds I remember being on one ot the tube stock main-line runs coming down from Amersham achieving over 70 mph
-someone can no doubt correct After the brakes came on hard for the Rickmansworth curve there was a distinct wheel-flat making itself very obvious.
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Post by nickf on Sept 10, 2015 15:52:32 GMT
Cecil J Allen said that in Edwardian times, the speed of GER J69s on Chingfords was "nearer to 60 than 50" across the Marshes. Surely the determining factors would have been distance between stations, gradient, and signalling? I can't imagine an A class exceeding 25 save out in the far reaches of the Met... For what it is worth, here is Fred T. Jane writing about a trip around the Circle on the footplate of a steam locomotive. I hope this worksYou will see that between Farringdon and Kings Cross the speed is estimated to rise to 40 mph, but for most of the time 20 - 25 mph is the maximum. Sorry about bad link earlier on - I think I have fixed it now. |
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Post by nickf on Sept 11, 2015 8:49:19 GMT
Apologies for bad link - see above for new version.
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class411
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Post by class411 on Sept 11, 2015 11:31:04 GMT
Excellent snippet, Nick, thanks very much.
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roythebus
Pleased to say the restoration of BEA coach MLL738 is as complete as it can be, now restoring MLL721
Posts: 1,255
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Post by roythebus on Oct 3, 2015 0:40:23 GMT
I've recently read an article in Railway Magazine I think regarding the GNR electrification plans pre 1910. That stated the average speed of steam hauled suburban trains was 18mph using 0-4-4T locos designed by Stirling. That may help the original question being answered.
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Post by twihlet on Nov 19, 2015 15:03:57 GMT
Thanks to all for these replies. I guess it was up to the state of the track and the muscles of the fireman.
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