Aristo EMD GP-40

A nice new loco, following the new Aristo policy of smaller locos for tighter curves:

Santa Fe only had one of these, and the model has the correct road number. It's a good looking loco, with the standard Aristo "prime mover" gearbox system.

But, now, after about a year of use, many people are reporting many different problems. The coupler problem was obvious right away. In early 2009, I noticed many posts about failing plating on the wheels. Since Aristo diesel wheels are steel, they will rust and pit quickly, bad power pickup.

In late 2009, there were several reports of the motors literally going up in smoke. Ted Doskaris is still investigating, but the common symptom is the motors start drawing a lot more current than normal, and heat up and smoke. I suspect inferior motors, specifically poor quality insulation on the motor windings, that is not the proper high temperature enamel, but a cheaper lookalike.

Axel Tillman, whose motorized switch machine Aristo so blatently copies, noticed this inferior insulation on the Aristo motor in their clone.

First run problems:

Quite a few people have reported couplers "coming apart" on the GP40 where the identical train on another Aristo loco is fine. It appears that the batch of couplers either have greater knuckle flex, or possibly the castings have "shrunk" more than usual. In any case it's true, and it's the couplers sliding apart sideways, not the knuckles popping open!

In late 2009, I started getting reports of the loco's "burning up". There's now all of a sudden 3 documented cases of the motors themselves drawing excessive current. In 2 of these cases, the motor itself is confirmed to be the problem, drawing huge amounts of current with no load (removed from the gearbox!) and smoking!.

It sounds like there may be a "lifetime" issues with these motors. Will keep you informed, but if you buy a used GP-40, be sure to watch out for this.

Electrical considerations:

This loco has a ton of polyswitches. It appears that they are in the battery buss ("mu cable") and on the main board. If you run heavy loads, or use the mu cables to run more than one loco, you will most likely have to bypass these. As always try to protect from shorts. This means an intelligent rewire. In a perfect world, on each of the pickup wires from the trucks would be best, along with one of the leads to the main board, but it's your choice.

Here are some pictures of the circuit boards inside, courtesy of John Burden:

Front PCB:

Rear PCB:

Misc Data:

The GP-40 uses a Mabuchi 545 motor with a fan.

Kadees:

 Even though the Kadee site gives different recommendations, I suggest that you read Ted's vignette for installation, and a better solution in my opinion.