Hi there. I wanted to just do a quick post to share this with everyone since I've read from time to time about Rokuhan transformers shorting or not running well with certain locomotives. Well this has happened to me too. A number of times. And it occurs to my Marklin Casey Jones locomotives that normally run amazingly smooth. I have to say that this has happened from both Rokuhan and (today) the Snail Speed Controller too (from Ztrack). I'm not blaming anyone but obviously there's something about diff controllers and how they play with Marklin. My experience today (and other times) is that the offending locomotive would just stall - and basically act dead. No amount of cleaning, lubricating etc will help. In the past I've been disheartened thinking that the locomotive truly had a malfunction. However the trick is just to power up the track with an original Marklin Miniclub transformer and well - I can only explain it in layman terms - it seems to give a jolt to the heart of the Marklin loco. If there are others out there who like me, aren't too familiar with circuit boards or capacitors or currents - I encourage you to give this a try if you've ever experienced a comatose locomotive!
A DC electric motor can require from 3 or 4 times it's normal operating current when starting. Depending on what position the armature comes to rest the last time you ran it. This will be most noticeable with the 3 pole motors. It sounds to me that the amount of current the snail and Rokuhan can deliver is marginal for the Casey Loco. The Marklin power pack must have a lower internal resistance and is therefore able to hit the loco with a good strong whack of current and start the armature rotating. Most locos made today use 5 pole or coreless motors and will never exhibit this problem.
It may be more than just the starting current. Any random binding, etc, can create a peak trip current. I am more worried about the overall health of the motor, 'cleaned & lubed' or not. You need a DC Amp meter. $5 or $50. It must be able to display at least 1 amp (1000 mA). Many will only do o.1 or o.2 A and then 10 Amp. The 10 Amps is a start though. If you have access to resistors (you will need ~ 1 Watt), you can place the resistor in series with the motor (either wire is OK). For a 1 ohm resistor, there will be 1 Volt for 1 Amp and o.1 Volt for o.1 Amp. A 10 Ohm resistor will make 10X the results (1 Volt at o.1 Amp) The motor should be somewhere around o.1 Amp, but nowhere near o.25 Amp. There were some bad production years, about 10 years ago. I had many directly new and spare motors that drew *much* more current than they should. You may have one.
I've never had any problem running any locomotive from any manufacturer with either the blue or gray/white Marklin transformers or the modified MRC 1300. I have had problems using the Rokuhan or snail speed controllers, though.
