RS-3 Improvements

Better wheels and gauge

If you have traction tires, replace them with wheels without tires, the traction tires put uneven force on the drive train, resulting in premature wear, but more importantly they actually cause derailments by the combination of uneven traction and the torque applied to the trucks. That's the best way I can describe the interaction between the "suspension", truck pivoting and the screwy design where one axle is rigid and one pivots along the truck axis. When you read about people swapping the trucks to make the floppy axle at one end, or changing other stuff around, realize that this is all related. I tried the "truck swap" trick, and sometimes it made a difference and sometimes not. I found that removing the traction tires eliminated all the derailments I was experiencing, and my observations were that the axle with the traction tire, having more grip, would "push" the truck such that the other axle would climb up off the rail (go airborn) and once the flange cleared the rail I had a derailment.

Protection from burned up main board and wiring.

This problem is not unique to the Aristo-Craft locos, it's a common problem with ANY track powered locomotive.

The issue is a short circuit through the locomotive wiring. For example: when any track powered loco derails at a switch, often a short circuit occurs. This is caused by the wheels on a truck getting the "wrong" polarity:

  • Loco derails on a switch. Front truck is derailed, sort of between the straight through and the diverging track.
  • Rear truck is "proper" polarity, let's assume left wheels negative, right wheels positive.
  • But front truck is messed up, and the left wheels land on the "wrong" rail, so the left wheels are now positive.
  • So you have a short circuit IN the loco:
    • Rear truck left wheels negative
    • But now the front truck left pickup is positive due to the derailment.
    • So power in a dead short of track voltage travels from the left wheels of the front truck, through the pickup wires, through the main board, and to the rear truck wires, to the left wheels of the rear truck and to the left rail.

So now the dead short of track voltage is THROUGH the created. Think about it, it is easy to happen.

So, the weakest link goes first, could be pickup wires, springs in the pickup skates, or as the picture below show, the traces on the main board.

With most layouts, there is enough current for 3 to 5 locomotives, often 10 amps or more. Many people run 25 amp supplies.

Interestingly, a short within the locomotive MAY NOT trip your 25 amp circuit breaker, but it can cause a lot of damage, i.e. the short might only draw 5 or 10 amps. Think about it. A 25 amp power supply will supply10 amps all day long, and even YOU know you have a short somewhere, it's not enough to trip the 25 amp breaker. There are no "brains" in an ordinary circuit breaker.


How do you prevent this? The best way is fuses or circuit breakers from each pickup wire on each truck. I use polyswitches. They are self-resetting thermal breakers, the heat from an overload makes them "open". I found some faster acting ones than the typical 3 amp ones you find in Aristo locos, but anything will work ok.


Below you see the chassis modified so I'll never melt down a board again. You need to protect each "side" of each truck. Note that this still will not protect from a short between 2 wheels on the same side of the same truck, although this seems rare, it can happen. Just wire the polyswitches on each track pickup wire.

Note, even with this protection, you could STILL theoretically have a short between the 2 wheels on a single truck, and destroy wiring inside the truck itself. This kind of short is more rare, and I did not protect from this, but you COULD put a polyswitch in the wiring between the 2 wheels on each side of the truck inside the motor block.

Additional speaker

The new QSI Titan decoders have 2 separate sound outputs, and you can "fade" or direct any sound to either speaker in increments.

I decided to try to "move" some sounds from the speaker in the loong hood to nearer the cab, notably the horn and bell.

Where to put the speaker? No convenient vents in the top. So I cut out some windows in the cab, and installed a speaker firing into the cab. I've not played with the settings much yet, but I can see it will be effective.

I used a small Phoenix speaker SP-36mm: 824-360 usually used for On3 installations. It is 36mm square x 14.5mm high and puts out a lot of sound for it's size.

I carved out a hole in the wall of the cab next to the short hood. Note well: You will run into the wires that power the cab light. My cab light was burned out, so I took this opportunity to remove the bulb and put in a LED.

Here's the results:



Weather Underground PWS KCACARLS78