Improving Power Pickup on the Mallet (and any Aristo steam loco with a tender)

 

The mallet tender has the typical Aristo wiring, there is only pickup from two wheels out of the eight in the tender.

But wait, it gets better:The tender pickups are only active in the "battery position", thus you can pick up from the locomotive drivers or the tender pickups but not both.

In addition, there is a backup light on the USRA tender and the Vanderbilt tender.

Therefore, you cannot do my Mikado "trick" and "steal" the "motor" wires for the speaker, since you need them for the backup light.

Wire the tender as in my Mikado example, pickups on all 4 axles (gives you 4 wheel pickup, not 2 wheel). Be sure to put the pickup wires on the tender board "battery" traces, right rail to right side trace on the tender board, left to the left or "inner" trace.

Now you need to make the pickups useful. Remove the 2 wires from the "battery" part of the locomotive circuit board.

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You now want to connect these 2 wires to where the driver pickups go. Luckily, there are 2 through holes in the locomotive board where you can place and solder these wires from the top side.

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Be sure to confirm that you are connecting the right wires to the right places! Do NOT rely on the color coding as shown in the picture. To make things even more confusing, in the original wiring, the battery wires connect to the switch pins as you would expect, the right hand rail connects to the rearmost right hand pin on the switch, etc.

BUT! The other 2 pins of the switch are reversed, i.e. the right hand pin on the far terminal is connected to the LEFT rail, and the left pin on the switch is connected to the RIGHT rail.

So, using an ohmmeter, verify which wire is the right rail tender pickup. Place it on the trace that goes to the LEFT pin on the switch. Verify that the other wire is connected to the left rail tender pickup and connect it to the RIGHT pin on the switch.

Now your locomotive will run much better on dirty track. 

Weather Underground PWS KCACARLS78