70014IronDuke
Established Member
- Joined
- 13 Jun 2015
- Messages
- 4,094
Taken from the thread
"Proposed Transfer of Bulleid MN's to the London Midland Region of BR" by alexl92, as this is essentially a new topic.
Bevan Price did thus opine:
On the subject of WCML dieselisation - does anyone know why Class 40 was chosen as the main steam replacement, when higher powered "Peaks" were also available ?
In terms of maximum power output, Class 40s were grossly inferior to any pacific, and not a great deal better than a Black 5. With typical heavy WCML loads at that time (often 14 - 15 Mark 1 coaches), Class 40 acceleration was painfully slow -- and speeds up Shap often fell to 25 mph or less. The extra h.p. from a Class 45 (or even a 44) would have been very useful on these trains.
(Of course, Class 40 was more consistently able to produce maximum power than rundown steam locos with inferior coal supplies.).
To which, 70014IronDuke retorted:
Class 40s were ponderous for diesels, but I don't believe they were "grossly inferior" to Class 8 steam. How fast would a Duchess go over Shap and Beattock unassisted with the loads you cite? More or less the same, ie 25 mph, I suspect.
It is difficult to remember what they were like on the WCML from personal experience (though I did get Class 40 haulage, but was too young to notice). However, on the Midland, from 1960 to 62 there were two trains that quite often had Class 40s- the 13.55 St Pancras - Manchester LR/Picc (almost always a Cl 40) and the up equivalent, approx 12.15 ex Man LR/Picc - St Pancras - which generally had a Cl 40 on Saturdays. I saw these trains many times. They were timed for Class 7 haulage at a mile-a minute Leicester-London. The Cl 40s kept time when used as well as any Brit or Scot.
I never saw Cl 5s on these trains, and I very much doubt that a Class 5 could have kept time with them unless handled by a very enthusiastic and skilled crew.
Bevan Price countered, seemingly with devastating effect:
The Railway Performance Society reported on the preserved Pacific time trials between Crewe & Carlisle in 1995. With load 11 coaches, minimum speeds up Shap & (average) equivalent db.h.p. were:
60007 (A4) 36mph / 1743 hp
46229 (Duchess) 42mph / 2201 hp
71000 (Duke of Gloucester) 51mph / 2358 hp.
With a similar 11 coach load, I had 25 mph from a Class 40.
Now, the steam locos were specially prepared for the trials. In the late 1950s and early 1960s, they were often getting a bit run-down, and mostly unable to match the 1995 performances. But, even so, they were clearly able to out-perform a Class 40, which would give, at best, an "at rail" power of 1400 - 1500 hp.
My own best runs in the 1960s were 36 mph minimum up Shap by 46256 (Duchess) and a 12 coach load, whilst 60007 (A4) managed 47mph with 11 coaches.
ENDS
But 70014IronDuke, struck back:
Bevan Price: "Now, the steam locos were specially prepared for the trials. In the late 1950s and early 1960s, they were often getting a bit run-down, and mostly unable to match the 1995 performances. But, even so, they were clearly able to out-perform a Class 40, which would give, at best, an "at rail" power of 1400 - 1500 hp."
But it is not only that the steam locos - the crews would have been especially keen to peform too. Notwithstanding the fact that these outputs are astonishingly impressive (71000 @ 51 mph in particular - must have been quite a roar!) such performances would not have been achievable on a day-to-day basis, unless, perhaps, oil-firing had been employed.
While I can accept that a Duchess (or, indeed, any Class 8 loco) could outperform a Cl 40, possibly on a daily basis, what I am questioning is this:
"Class 40s were grossly inferior to any pacific, and not a great deal better than a Black 5."
As I pointed out (yes, I know it's a rather unusual example, but it's the only one I can cite personally) - on the tightest day-to-day timings applied to Brit/Royal Scot Class 7s on the Midland, the Cl 40s had no trouble whatsoever in maintaining schedules.
[I should be honest and say that the up train was sometimes Jubilee-hauled, which also managed to keep time. I never saw anything less than a Cl 6 on these trains.
On one occasion, the up train was a Cl 45 about 50' late - almost certainly due to failure of the train loco, I'd assume.]
In my final piece of evidence, I believe it was Gerard Fiennes who wrote something like: "We realised that the EE4s were no better than a pacific in fine fettle." (My emphasis.)
He may have meant or even mentioned an A3, of course, which was only a Cl 7 in the BR ratings.
"Proposed Transfer of Bulleid MN's to the London Midland Region of BR" by alexl92, as this is essentially a new topic.
Bevan Price did thus opine:
On the subject of WCML dieselisation - does anyone know why Class 40 was chosen as the main steam replacement, when higher powered "Peaks" were also available ?
In terms of maximum power output, Class 40s were grossly inferior to any pacific, and not a great deal better than a Black 5. With typical heavy WCML loads at that time (often 14 - 15 Mark 1 coaches), Class 40 acceleration was painfully slow -- and speeds up Shap often fell to 25 mph or less. The extra h.p. from a Class 45 (or even a 44) would have been very useful on these trains.
(Of course, Class 40 was more consistently able to produce maximum power than rundown steam locos with inferior coal supplies.).
To which, 70014IronDuke retorted:
Class 40s were ponderous for diesels, but I don't believe they were "grossly inferior" to Class 8 steam. How fast would a Duchess go over Shap and Beattock unassisted with the loads you cite? More or less the same, ie 25 mph, I suspect.
It is difficult to remember what they were like on the WCML from personal experience (though I did get Class 40 haulage, but was too young to notice). However, on the Midland, from 1960 to 62 there were two trains that quite often had Class 40s- the 13.55 St Pancras - Manchester LR/Picc (almost always a Cl 40) and the up equivalent, approx 12.15 ex Man LR/Picc - St Pancras - which generally had a Cl 40 on Saturdays. I saw these trains many times. They were timed for Class 7 haulage at a mile-a minute Leicester-London. The Cl 40s kept time when used as well as any Brit or Scot.
I never saw Cl 5s on these trains, and I very much doubt that a Class 5 could have kept time with them unless handled by a very enthusiastic and skilled crew.
Bevan Price countered, seemingly with devastating effect:
The Railway Performance Society reported on the preserved Pacific time trials between Crewe & Carlisle in 1995. With load 11 coaches, minimum speeds up Shap & (average) equivalent db.h.p. were:
60007 (A4) 36mph / 1743 hp
46229 (Duchess) 42mph / 2201 hp
71000 (Duke of Gloucester) 51mph / 2358 hp.
With a similar 11 coach load, I had 25 mph from a Class 40.
Now, the steam locos were specially prepared for the trials. In the late 1950s and early 1960s, they were often getting a bit run-down, and mostly unable to match the 1995 performances. But, even so, they were clearly able to out-perform a Class 40, which would give, at best, an "at rail" power of 1400 - 1500 hp.
My own best runs in the 1960s were 36 mph minimum up Shap by 46256 (Duchess) and a 12 coach load, whilst 60007 (A4) managed 47mph with 11 coaches.
ENDS
But 70014IronDuke, struck back:
Bevan Price: "Now, the steam locos were specially prepared for the trials. In the late 1950s and early 1960s, they were often getting a bit run-down, and mostly unable to match the 1995 performances. But, even so, they were clearly able to out-perform a Class 40, which would give, at best, an "at rail" power of 1400 - 1500 hp."
But it is not only that the steam locos - the crews would have been especially keen to peform too. Notwithstanding the fact that these outputs are astonishingly impressive (71000 @ 51 mph in particular - must have been quite a roar!) such performances would not have been achievable on a day-to-day basis, unless, perhaps, oil-firing had been employed.
While I can accept that a Duchess (or, indeed, any Class 8 loco) could outperform a Cl 40, possibly on a daily basis, what I am questioning is this:
"Class 40s were grossly inferior to any pacific, and not a great deal better than a Black 5."
As I pointed out (yes, I know it's a rather unusual example, but it's the only one I can cite personally) - on the tightest day-to-day timings applied to Brit/Royal Scot Class 7s on the Midland, the Cl 40s had no trouble whatsoever in maintaining schedules.
[I should be honest and say that the up train was sometimes Jubilee-hauled, which also managed to keep time. I never saw anything less than a Cl 6 on these trains.
On one occasion, the up train was a Cl 45 about 50' late - almost certainly due to failure of the train loco, I'd assume.]
In my final piece of evidence, I believe it was Gerard Fiennes who wrote something like: "We realised that the EE4s were no better than a pacific in fine fettle." (My emphasis.)
He may have meant or even mentioned an A3, of course, which was only a Cl 7 in the BR ratings.
