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Model Railroading > Steam pickup wipers for sound and general connectivity

Date: 02/13/21 13:17
Steam pickup wipers for sound and general connectivity
Author: Jeff_Johnston

In my post from yesterday, "Audio for SPLCo #1, and #5, too" I mentioned that I " ... added pickups to two more drivers and the trailing truck" in reference to a recent sound installation on a couple of our Sugar Pine Lumber Company tank locos. I've had a few inquiries about the specifics of those added electrical contact wipers. I hope these images help explain things and I apologize for the rough drawings but I think you'll get the picture.

Drawing #1 shows an exploded view of the rear-wheel driver wiper added to the #1 2-8-2T. The wiper material is .003 inch Phosphor-Bronze purchased many years ago from Clover House, I'm not sure if it's even available from them or their successors any more. My use of Walthers Goo adhesive has worked fine with many years of service and no failures.

Drawing #2 is a cross section showing how the pieces fit on the frame and the spacing with the driver tread.

In Photo #3 it's almost impossible to see the bracket without removing the body, but you can see the straight wiper on driver #3 and the bent-forward wiper on driver #4. The bend was necessary due to space constraints.

The next post shows the trailing truck wiper assembled using the same technique minus the bracket.

Jeff Johnston

Date: 02/13/21 13:21
Re: Steam pickup wipers for sound and general connectivity
Author: Jeff_Johnston

The trailing truck wiper. The rectangular piece at right is a lead weight added to enhance tracking as well as keeping the wheels spinning when the wiper might want to slam on the brakes. This unit required some fiddling with the wiper adjustment but it works fine once tweaked. The green is Liquid Electrical Tape (I was out of black) added as an extra insulating step to help avoid shorts.

Jeff Johnston

Date: 02/13/21 13:32
Re: Steam pickup wipers for sound and general connectivity
Author: funnelfan

I did something similar with brass wire, but I had it rub against the back of the tires to keep it out of view. Works great! Then with the addition of the keep alive circuit, it's pretty much flawless running now.

Ted Curphey
Cheney, WA

Date: 02/13/21 14:16
Re: Steam pickup wipers for sound and general connectivity
Author: Jeff_Johnston

I've thought about those backside wipers but have never been keen on the idea of consistent lateral pressure being applied to a driver set, pushing the drivers towards one side of the frame. I know there's not much pressure from a fine-gauge pickup wire and the system works for people so obviously it's a paranoid technical "thing"on my part. My pair of PSC 2-8-2T locos, SPLCo #2 and #3, have lateral spring-loaded pins through an insulated frame bushing with the pins contacting the wheel backsides. These will definitely be replaced with tread wipers.

As for the tread wipers being visible, I always choose function over form, within reason. And if anyone looks that closely at my locos and sees the wipers and has his or her operating or viewing enjoyment degraded because of that minimal wiper visibility, well, that's one of those problems I can't get too worked up over.


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