Maximum Loadings for Diesel Locos

QUOTE (Saint Johnstoun @ 15 Mar 2009, 19:27) <{POST_SNAPBACK}>I've been extending my layout and can now handle 10 coach trains with ease. Now I have a pretty good idea as to what prototypically most of my steam locos can handle but when it comes to diesels I have scoured my extensive library and cannot find any loading information anywhere.

Can anybody advise what maximum loadings ( in passenger coach numbers) would be for a type 2, a type 4 and two type 2s in multiple?

The only diesels I have are early Scottish Region examples of classes 24, 25, 26, 27 and 40.

Without taking into account difficult hilly terrain, I can let you know what I saw in my area in the late 70's and early 80's on an easy relatively level road.

Class 24 - 7/8 BR Mk1's
Class 25 - ditto
Class 26 - Pass
Class 27 - Pass
Class 40 - 11-12 Mk1's

In those days we had ceased to see the massive 14+ coach trains seen behind Duchesses etc and 12 was about the max - even for more powerful locos like classes 47 and 50.

I do remember the Class 27's on the original push/pull Glasgow-Edinburgh services and they were used in multiple on 7/8 coach sets to provide sufficient acceleration - later replaced by a single 47 onthe same amount of coaches.

In theory the type 2's should have had about 5 mk 1's, six at a push, the couple of type 3's would have been pulling about 8 whilst the type 4's should have got up to about 12 mk 1's. (The odd one out is the class 33 - just a type 3, it really seems as if it should have been a type 2.)

In practice all of the diesels were thrashed well beyond what they were originally designed for !

It was a question of expediency over reliability and longevity. The steam engines seemed to be able to cope with overloading, perhaps because it had gone on for so long or perhaps the workshop routines were better able to repair the worn out parts.

For the diesels, the overloading shortened the life of the engine so that some had a noticably better performance after having a scheduled visit to the shops. My impression (not based on hard evidence) was that the Sulzer engines were not as good at surviving thrashing as their English Electric competitors but latterly, the class 50 seemed to be worn out so who knows ? Perhaps the Sulzers were more highly stressed than the EE engines.

In the early days when the diesels were not as reliable as they later became, it wasn't unusual to see the smalle classes doing the work of the bigger stuff, so you could probably model what length train you fancy.