Clovelly Road

The amount a loco slows down on tight curves (or gradients) depends a lot on the type of controller you use.  If you did the tests with DC then a 'feedback' type of controller would attempt to compensate for the load on the motor and maintain a constant speed.  I suspect DCC systems will do similar compensation but am not familiar with how they work in practice.

 

i agree, however, that 'fettling' tight curves is desirable.  Apparently Stephenson originally chose 4' 8" gauge but had to add the extra 1/2 inch to help the wagons go round curves!  Brunel increased the 4' 8" by 50% (good engineering rule of thumb, when changing things) to 7' but also found that he needed to add a bit, but only 1/4 inch because his curve radii were larger.

Equally important for good running when running around tight curves is that you should use transition curves. This means that the radius should gradually get tighter and you should avoid a sudden changes of the radius.

 

Julie

What causes the slackening of speed, whilst negotiating a curve is the flange on the wheel on the outside of the curve rail coming into contact with the inside face of said rail.

 

That is why on the prototype the a check rail is place alongside the inner rail, to pull the wheelsets across to prevent the out wheel flange coming into contact with the rail edge.

 

Lisa

I would have thought that friction on the check rail would be just as great?  I do have check rails on some of my tight curves but they are to stop the flanges 'jumping' the outer rail