BR STANDARD STEAM LOCO FOR SALE

Trouble is when it comes to steam loco's the "lookers" tend to sods to maintain compared to the "ugly ducklings"

 

This is not just theory, but a potential problem in practice for all two cylinder locomotives. If the reciprocating motion is not properly balanced, then in extremis at high speed, the hammer blow can become excessive and driving wheels can lift off the track once per revolution. This was very vividly demonstrated by Stanier's experiments with a (static) Black 5 on heavily greased rails which was filmed using various different wheel balancing configurations. The problem is that the reciprocating motion on 2 cylinder engines can't be perfectly balanced and there is always a compromise between the residual vertical hammerblow and the oscillatory horizontal forces which lead to fore-and-aft shuttling. 4 cylinder engines don't really have this problem as the reciprocal motion for one cylinder is naturally balanced by another cylinder where the motion is moving in the opposite direction.

David

 

A hall would be struggling to match that top speed and is not going to be able to accelerate the train as fast i would guess. I am assuming the train is going to be 12 + mk1s with catering

 

Maybe that's overstating it a bit. There can be hammer blow issues with 4Cyl locos as well, especially with divided drive. Churchward reworked the wheel balancing of the Stars after the Bridge stress committee work - see here Great Western locomotive types .

Balancing steam locos is a pretty complicated subject - too complicated for here even if I fully understood it - because one end of the connecting rod is going to and fro and the other end going round in a circle, all the components are running out of phase with each other and weight and wear must be minimised. All these factors fight against each other to make the designers' task extremely "interesting".

 

Edited

 

So in Hindsight all BR Had to do was build afew nore 9FS, Balance 100 or so for fast runninng and there wouldnt have been a need for Brits, Clans and perhaps even 5's... (