General Discussion

Hello OO live steam community.

As a proud new owner of a used Mallard set, I do enjoy the special flair of this kind of model railroading. Especially because I seem to have picked a quite smooth runner. At least running forward. Starting in reverse is a little more challenging in times.

Looking into various books on steam locomotives, I had the idea to start a playful "scientific" approach to the model. I am not sure, if this has been done by others. At least I could not find something in the forum so far.

What do I mean by "scientific approach"?

There is a bunch of mathematical formulas describing steam locomotives. You can calculate the cylinder power, the pulling power, energy consumption,....

Of course all this will be connected with a lot of inaccuacies due to the small size of the enginge and the precision of measurement tools available, but hey why not try?

To start with the calculation of the cylinder power of the locomotives, I miss some data of the Mallard model: The piston diameter - do not want to dismantle my model :-) and some information about the cut-off. I estimate the valve gear should cut-off somewhere between 80% and 100%.

Can somebody help there?

So far for the first theoretical step, now for the practical one: There is a number of "testruns" I can imagine.The most obvious is water consumption - reachable distances with one water filling with certain changing parameters (speed, heating setting, number of coaches, ambient temperature)

An important helper for these kind of runs will be the Fleischmann Tachowagen 5555, which is basically a dynamometer car for speed time and distance based on a bicycle speedometer mounted on a freight wagon chassis.

With some intermediate steps and some luck, the mathematical values and the practical measurements can be put together.

Is there somebody out there who has already done something like this?

By the way: Here are the results oft he first „official“ testrun“

Ambient conditions 16 °C; humidity 43 %

Track: set oval on the floor

Train: 5 Lima express coaches, 1 Tachowagen

Water filling: 22 ml

Non stop running time (until water was gone): 28 min 54 sec

Travelled distance (1:76 scale): 63,38 km = 39,39 mi

Max speed (1:76 scale): 184,4 km/h = 114,6 mph (this was from the "turbo phase" when the cylinders had warmed up. I did reduce throttle for a lower cruising speed then)

Avg speed (1:76 scale): 131,6 km/h = 81,8 mph

next planned run with lower speed

kind regards

ICE/V