Chuck Furlong devised a solution to the older Alco engine
chassis (ie the 360 Santa Fe) that didn't come with electrical sliding pickups
on the trucks. Here is Chuck's explanation of his project - and a few pictures
to emphasize the details.
The need for these sliding contacts was painfully demonstrated
to me after running a freshly serviced 360 Alco PA on clean track. I was used to
the behavior of a 470 Rocket Alco (which we purchased a few years before). I never had any trouble with wheel arcing or
with that loco putting dirt
on clean track (it has factory-fitted sliding contacts).
But, when I applied power to the 360 (after spending several hours getting it all
cleaned and lubed), I was crestfallen to find it lumbering along, spitting sparks from under it's current pick-up wheels, and leaving freshly
cleaned track with black deposits. I cranked the throttle open wider to try "powering through" the conditions, but that didn't help
matters. The sparking got worse with each lap of the main line. Then, when I removed the side frames and looked into the trucks (after a
mere few minutes of these fireworks), I was astonished to find that all of the newly applied lubricants I had so carefully massaged into
the axle bearings had disappeared! There was still grease on the axles between the gears and the truck chassis, but none in the
bearings proper. Then, it dawned on me: without pick-up shoes, all of the current had to go through the wheels, the bearings, and the
lubricants in the bearings. Lubricants seem to resent being zapped with substantial
amounts of electrical current. They respond by evaporating, it seems. No wonder these wore out so fast, and no
wonder that Gilbert resorted to sliding contacts for the main current path into these hungry beauties.
I've heard of some folks replacing the side frames on 360 diesels with later slide contact equipped frame assemblies. I resorted to making
slip-in contact wipers out of sheet brass, brass angle, and #2 machine screws. The difference in performance is dramatic, like night
and day. Now I can run the 360 for hours without so much as a single spark. Also, the lubricants remain intact and in place, which is no
small advantage.
AF Alco slide pick-up shoe info: materials and dimensions...
The base mount of the shoe is formed from a 1/2" length of 1/4" brass angle. The bottom (horizontal) side of the angle is trimmed to about
1/8" (or slightly less). A U-shaped slot about 1/8" wide is cut into the center of the vertical side of the angle, down to about 1/16"
from the bottom. The resulting "fork" will slide under the head of the yoke screw.
Soldered to the base lengthwise is a "leaf" contact 1 3/4" long and 1/8" wide, made of 0.005" sheet brass. (Copper or bronze of the same
thickness would be better, but brass is adequate.) The longer leaf end should be 25/32" from the nearest base end. The leaf will need to
be located on the bottom (outside) of the base, with the leaf's outer edge protruding just slightly outside the vertical part of the base.
This may take some experimentation; the exact side-to-side position of the leaf depends on how "bowed" your
side frames may or may not be, as well as how much side-play the wheels have.
Soldered on top of each tip of the leaf is a 1/8" square piece of brass about 0.030" thick. This will provide some "meat" for screw
threads.
Screw hole centers are 3/32" from the ends, centered side-to-side, bored with a #50 drill bit. After tapping with a 2-56 thread tap, 2-56 machine screws can be inserted from the bottom up. Any excess
shank will be cut away, so it pays to use the shortest screws available. I used round head screws, and ground the heads flat
slightly to get more wheel clearance and smooth-out tracking. That chore could have been avoided (probably) by using pan head screws. I
don't recommend counter-sunk screws for this.
Since screws have been employed here for durability as well as replace-ability, I used steel screws instead of brass. If I'm not
mistaken, stainless steel screws are a bit harder than normal steel, and should wear even longer. Not having worn these out yet, I don't
know just how long they will last.
Most of the actions above were accomplished with the help of a moto-tool to cut, grind, and shape. A 25 watt soldering pen was adequate
for all soldering, given the small size of the parts. The materials used are available at any hobby shop worthy of the term.
You may contact Chuck via e-mail for more information at
