I wonder whether some one could help me with enquiries about clockwork controlled locomotives, such as the Walker-Riemsdyk (or Riemsdijk) 0-6-0 tank engines which Martin is planning to use on the incline between the upper and lower levels of the Rivermead Central layout, please?
1. Does the setting of the variable speed control disc affect the length of run? I would surmise that it does not: the gear train between the mainspring and the driving axle is not itself variable, and a given number of turns of the key would, it would appear, result in a corresponding number of turns of the driving axle, irrespective of the rate at which the spring is released.
Very little, if at all. The residual power in the spring probably does become insufficient to move the loco/train slightly ‘earlier’ in the unwinding process when the loco is set at a slower speed.
2. Does the setting of the variable speed control affect the power output of the engine? Insofar as the control restrains by friction the release of the spring it would seem that setting a slow speed might reduce the output at the drawbar. But I may be mistaken about the physics/mechanics of these engines!
Yes, but not by that much. The loco will still pull a reasonable load at quite a slow speed, but it will pull more if the speed is set higher.
As it happens, I do possess one of the W-R engines. At present, operating the control disc seems to make little difference to the speed of the engine, but it may require just a simple adjustment.
The speed control is also the brake. When turned right down, the engine shouldn’t move even if fully wound. As the control wheel is turned, the loco should run progressively more quickly. I haven’t come across the problem you describe in the 0 gauge 0-6-0 tanks. I do have a rather larger van Riemsdijk motor which is very powerful. It’s just a motor sold for scratch builders. On test, the speed control on that motor won’t hold it stationary against the spring if fully wound. Built into a locomotive, maybe the extra friction/weight would make the speed control into an effective brake. So really, another clockwork scratch build is required to use this excellent and powerful motor …
A 1955 Walkers and Holtzapffel catalogue states (on page 35) that the engine was available in two versions: the 'standard' (100/110 feet run) 'for general service'; and a 'gradient type' (80/90 feet run) 'for heavy haulage'. Presumably this difference was achieved by alterations of the ratios between some of the gears in the train.
John
I have never found a loco I was convinced was the ‘gradient type’. However, I have seen versions of the 0-6-0 with larger diameter driving wheels. So perhaps these were the ‘standard models’ and the versions I have (with 5’ diameter drivers) are actually the gradient version.
If I found a loco or mech with a different gear train, that would give a definitive answer. But the difference described would be produced by different wheel diameters, which there certainly are.
Martin
P.S. I refer you to Tom Mallard’s work bench thread where he is working on one of these motors currently.
