Im going there next week,,ive just been asked to look into it for nene valley railways,the chief tech/engineer there is a friend of mine,as far as i can tell the control box/regulators are forever playing up,not suprising when you think some of the stuff is 100yrs old,testing could be interesting as as far as i know the dynamo is belt driven from the axle,i was thinking maybe using a modern ss 24v alternator regulator to power the field windings,shall know more when i get to see in the flesh what im working with,i dont know if each carriage has its own batterys/dynamo or what yet.