The pros and cons of class 37 v class 40 locomotives

[Richard Scott]

Maybe time for a Class 40 v 45 comparison too

Think performance wise a 45 would win hands down. 40 may have the edge on reliability but think 45s were pretty bullet proof.

 

[Cowley]

I never worked 'on the ground' with Class 37s but took it as an omen that literally when I arrived for my first ever supervisory shift there was a derailed Class 40 blocking the job and someone had to pick me up in a yellow BR van from a station along the line. A bogie problem had caused the '40 to drop on the deck on a crossover.

Needless to say the M&EE representative denied that there was a problem with the locomotive whatsoever and blamed the track.

On my third day I arrived at work to discover the same Class 40 derailed again on another crossover a couple of miles away.

At that point the M&EE representative conceded that there might be a rotational stiffness issue.

Never really trusted them after that but have to concede that they could shift a chunky freight train.

That’s a great anecdote @Dr Hoo.

 

[Inversnecky]

literally when I arrived for my first ever supervisory shift there was a derailed Class 40 blocking the job.

On my third day I arrived at work to discover the same Class 40 derailed again on another crossover a couple of miles away.

Whereabouts was this?

 

[Whistler40145]

Quite surprising that Class 40s with 2000hp seemed to lack power than a Class 37 with only 1750hp

Mind you, there's nothing more appealing to the ears than a 37 or 40 struggling on wet rails

 

[Dr Hoo]

Whereabouts was this?

Let’s just say “somewhere on Merseyside”.

 

[xotGD]

Quite surprising that Class 40s with 2000hp seemed to lack power than a Class 37 with only 1750hp

Mind you, there's nothing more appealing to the ears than a 37 or 40 struggling on wet rails

I remember one day when a 40 on the northbound anhydrous ammonia tanks was routed through platform 8 (as it was then) at Newcastle. Plenty of slipping, and the sound of the 40 under the station roof was a joy to behold.

 

[MrEd]

Quite surprising that Class 40s with 2000hp seemed to lack power than a Class 37 with only 1750hp

Mind you, there's nothing more appealing to the ears than a 37 or 40 struggling on wet rails

Perhaps this is because a 37 has a far better power-to-weight ratio (105 tons vs. 133, but only 250hp less) so is a lot less sluggish when accelerating with a passenger train?

 

[randyrippley]

Think performance wise a 45 would win hands down. 40 may have the edge on reliability but think 45s were pretty bullet proof.

The Sulzers in the 45 and 46 fleet were nearly as unreliable as those in the 47 - and like the 47, a lot of new crankcases were needed.
BR gambled on the 45 design and lost. What I don't understand is why they then compounded the problem by using the same engine in the 47, along with the inferior electrics from the 46. By the time the 47s were built both Brush and Cromptons were part of Hawker-Siddeley so I guess its possible that internal company politics within Hawker played a role. The obvious solution would have been to move Crompton production to Loughborough but maybe that was too simple?

Perhaps this is because a 37 has a far better power-to-weight ratio (105 tons vs. 133, but only 250hp less) so is a lot less sluggish when accelerating with a passenger train?

Must be more to it than that - remember the 40 was allegedly preferred on the WCML over the Deltic due to the 40's supposed better acceleration from low speed

 

[MrEd]

The Sulzers in the 45 and 46 fleet were nearly as unreliable as those in the 47 - and like the 47, a lot of new crankcases were needed.
BR gambled on the 45 design and lost. What I don't understand is why they then compounded the problem by using the same engine in the 47, along with the inferior electrics from the 46. By the time the 47s were built both Brush and Cromptons were part of Hawker-Siddeley so I guess its possible that internal company politics within Hawker played a role. The obvious solution would have been to move Crompton production to Loughborough but maybe that was too simple?


Must be more to it than that - remember the 40 was allegedly preferred on the WCML over the Deltic due to the 40's supposed better acceleration from low speed

I think a 40 is probably much better (because of its tractive effort and how it’s engineered) with heavy trains on steep gradients, both passenger and freight, which was probably what the WCML in the 60s needed. A Deltic would win hands down with a limited load, fixed-formation express on a flat, straight main line, as performance comparisons from the ECML between York and Darlington show. I seem to think that the Class 40’s main problem was that on fast, level main lines, it took an agonisingly long time to reach line speed. Perhaps this led ER drivers who also worked with 46s and Deltics to perceive them as sluggish.

At no point (except perhaps in their earliest years) were 37s ever expected to perform top link express work, so perhaps their limitations were less apparent to those who worked with them? Both 37s and 40s seemed well suited to secondary passenger and freight work. A 40 strikes me as an ideal freight loco, less so express passenger. I‘m just trying to think of a turn which could have been worked by both 37s and 40s so that maybe performance logs can be compared? I wonder how a 37 compared with a 40 on the Liverpool Street-Norwich run in the early 60s? There’s probably not that much in it.

 

[Whistler40145]

I think a 40 is probably much better (because of its tractive effort and how it’s engineered) with heavy trains on steep gradients, both passenger and freight, which was probably what the WCML in the 60s needed. A Deltic would win hands down with a limited load, fixed-formation express on a flat, straight main line, as performance comparisons from the ECML between York and Darlington show. I seem to think that the Class 40’s main problem was that on fast, level main lines, it took an agonisingly long time to reach line speed. Perhaps this led ER drivers who also worked with 46s and Deltics to perceive them as sluggish.

At no point (except perhaps in their earliest years) were 37s ever expected to perform top link express work, so perhaps their limitations were less apparent to those who worked with them? Both 37s and 40s seemed well suited to secondary passenger and freight work. A 40 strikes me as an ideal freight loco, less so express passenger. I‘m just trying to think of a turn which could have been worked by both 37s and 40s so that maybe performance logs can be compared? I wonder how a 37 compared with a 40 on the Liverpool Street-Norwich run in the early 60s? There’s probably not that much in it.

Regarding 40s on Liverpool Street to Norwich services, 40145 holds the record for non stop run first to Ipswich and then Norwich, which also breaks the non stop record for a Diesel loco

 

[Irascible]

Quite surprising that Class 40s with 2000hp seemed to lack power than a Class 37 with only 1750hp

Mind you, there's nothing more appealing to the ears than a 37 or 40 struggling on wet rails

More power at the engine doesn't mean it's got more tractive effort at a given speed, necessarily - improvements in the electrical gear can make what comes out a larger proportion of what goes in ( a vague rule of thumb was about 12% loss in the generator plus 12% or so in the motors, iirc - nowadays it's something more like 6% overall I think ), plus the actual characteristics of the motors etc. What motors did they use on 40s?

 

[Inversnecky]

Regarding 40s on Liverpool Street to Norwich services, 40145 holds the record for non stop run first to Ipswich and then Norwich, which also breaks the non stop record for a Diesel loco

Surprised you know that, ‘Whistler40145’!

 

[Whistler40145]

Surprised you know that, ‘Whistler40145’!

Well it's my favourite loco

 

[Inversnecky]

I meant that I thought the nose on a 40 looked slightly longer...

Interesting that the 40 is half a metre longer than the Peaks (21.18m v 20.70m): perhaps the Peaks have shorter noses, which makes them look longer?

To me, the 18.75m long class 37 looks best proportioned in terms of its nose to body length if we’re talking aesthetics (!)

Think the Deltics are the longest BR diesels at 21.18m?

 

[43096]

Think the Deltics are the longest BR diesels at 21.18m?

Class 60 is quoted as being 21.34m.

 

[Richard Scott]

More power at the engine doesn't mean it's got more tractive effort at a given speed, necessarily - improvements in the electrical gear can make what comes out a larger proportion of what goes in ( a vague rule of thumb was about 12% loss in the generator plus 12% or so in the motors, iirc - nowadays it's something more like 6% overall I think ), plus the actual characteristics of the motors etc. What motors did they use on 40s?

EE526, I believe, same as the 20s.