Difference in performance of class 31 & 37

[russ p]

21 minutes ago, Titan said:

 

Well with only 10 coaches on and nearly 3,000bhp on tap they bloomin well ought to be, ETH or no ETH!

 

Only one loco would be supplying ETH

[russ p]

22 minutes ago, Titan said:

 

Well with only 10 coaches on and nearly 3,000bhp on tap they bloomin well ought to be, ETH or no ETH!

 

Only one loco would be supplying ETH 

[45125]

On 15/12/2019 at 18:40, Zomboid said:

So (remaining off topic), would a deltic on one engine respond differently to the power handle depending on which cab it's being driven from?

Yes it does.

 

[Melton Works]

On 30/11/2019 at 18:26, Robert Shrives said:

31s are 100 plus tons  for a type 2 but a 26/ 27 around 70 tons  so the 31 has to lug more around so it is going to be poorer , it is just a statement of the times in which it was planned where steam engine designers were getting to hand with diesels. compare the D600 to D800 for how stressed light weight bodies came to the fore. 

Robert      

Plus lacking a couple of traction motors...

[woodenhead]

I saw a video this week of a class 31 hauling a fully loaded 30 wagon MGR at Warrington Arpley.

 

It was amazing, hardly showing any effort lugging something that usually requires a Type 4 or 5.........

 

 

 

 

It still had the two class 20s that brought it down from Wigan on the back 🤣

[Melton Works]

Class 37/4 = 55000 lbs tractive effort

 

Class 31/4 = 42800 lbs tractive effort.

 

Lack of two traction motors and overall weight seem to make the difference seeing as they have the same EE 12(C)SVT powerunit.

[woodenhead]

I guess that's what happens when you have to replace the designed traction with something else that happens to fit the space.

 

At least it was a more reliable unit that went in and the 31s remained useful to BR for many many years unlike other locos.

[Melton Works]

1 hour ago, woodenhead said:

I guess that's what happens when you have to replace the designed traction with something else that happens to fit the space.

 

At least it was a more reliable unit that went in and the 31s remained useful to BR for many many years unlike other locos.

I think it was a good move back then, to save the class and replace with EE powerunits and as you said, went on many years for BR. Infact it was the 31 that got me into all this, as a 5 year old, stood at the foot of Thetford station footbridge looking up at one of these beasts, pulling away at full thrash on the Norwich-Birmingham New St, was awe inspiring!

 

I have heard different opinions from Ex BR friends of mine on these machines. One of my mates Chris used to work them as a freight guard (Gt Ryburgh grain and Lenwade Concrete) and recons they were a joy to work with and drive, yet my mate Andy who was a guard Cambridge- London/Kings Lynn hated it when he got a 31 on a Sunday evening last trip home with 9 bogies, because he knew he was going to be late, appx 55 mph tops!

 

He also said they couldn't manage Bethnal green bank without turning the ETS off! He also said that if it was a Bounds green machine, it would fair slightly better, which makes me think maintainance had something to do with it too?

[tom s]

Figures of D5516's (1,250hp) 1959 road trials from Diesel Pioneers - David  N. Clough.

The author remarks that the 540hp required to move just the locomotive at 80mph seems dubiously high, but around 200hp being absorbed by the locomotive at moderate speeds.

Factoring that out, the 37 goes from being 31% more powerful at the motors to 38% more powerful at the drawbar. 
 

Edited December 24, 2023 by tom s

[25901]

7 hours ago, Melton Works said:

Class 37/4 = 55000 lbs tractive effort

 

Class 31/4 = 42800 lbs tractive effort.

 

Plus a very important factor most of you have missed

 

One Monkey driver +0% efficiency

One skilled driver = 100% efficiency

 

If you don't control your traction and run out of skill and sand, the hp means nothing

[Steadfast]

On 24/12/2023 at 12:52, Melton Works said:

Class 37/4 = 55000 lbs tractive effort

 

Class 31/4 = 42800 lbs tractive effort.

 

Lack of two traction motors and overall weight seem to make the difference seeing as they have the same EE 12(C)SVT powerunit.

The intercooler on the 37 will make a chunk of difference, too.

Isn't that what the C in the 12CSVT stands for?

 

Jo

Edited December 25, 2023 by Steadfast

[Cowley 47521]

2 hours ago, Steadfast said:

The intercooler on the 37 will make a chunk of difference, too.

Isn't that what the C in the 12CSVT stands for?

 

Jo

Yes for Charge Cooled I believe?

[Melton Works]

4 hours ago, Steadfast said:

The intercooler on the 37 will make a chunk of difference, too.

Isn't that what the C in the 12CSVT stands for?

 

Jo

Yes that's why I put it in brackets. The same as the 40 and 50. Big hp difference. Again big weight difference too. 2000hp and 133 tons unlike the 50 2750hp and quite lighter.

[Cowley 47521]

It’s interesting observing the differences between the intercooled versions of the EE power units compared to the basic turbocharged (SVT) ones. I had a run behind one of the Portuguese 1400s earlier in the year which have basically the same engine as a class 20 but with charge cooling produce an extra 350 (I think) horsepower and rev up much more quickly. Quite similar to the differences between a class 31 and a 37.