I added a tether between two WBB 44-tonners in order to make them run much better together. I had previously converted both to motors wired in serial and converted one to a calf. Here I show how I wired the tether and give the results of some tests of the speed and pulling power limits of the loco.
The WBB 44-tonner is well-made and heavy but very challenged because it has only two of its four axles are powered (innermost axles at each end). But it can't pull a lot: of the more than 100 locos I run, these have the worst traction and pull the least.
Also, my experience is that they have marginal electrical pickup: at least my two did. Running individually, they "stutter" a bit as they run, particularly over some switches, and occasionally refuse to start up and have to be nudged. Running as a pair, without a tether, they are particularly frustrating: one of the other usually experiences a "dead contact event" and the two-unit train not only stumbles badly for a second, but e-units fall out of sync and they now fight each other. The tether solves these electrical problems: they run smoothly, slowly, steadily and that helps them pull. But they still don't have great traction.
Comments:
- I know that the couplers are metal, and electrically connected to the bodies (I tested them): so one could scrape a bit of paint leaving bare metal on the inside of each and hope they tie the outer-rail pickup of the locos together. This does not work that well: I tied the center pickups only together with a one-wire tether, and while they ran well, the pair still stuttered, just not as often. So I tied both the center-rollers and outer-rail (chassis) together with the tether.
- I did not want to disassemble these puppies again, both because it's a lot of work, and it is nearly impossible to do so and not damage the railings, requiring delicate surgery to repair. So I added the tether without take them apart.
First, which end of the locos to couple so their e-units are coordinated as to direction? There is a tiny "F" on the chassis on the front of every unit.
Again, I did not want to disassemble the locos. I looped a thin wire (red) around the frame of the center pickup. I made a loop on the end of a wire (black), scrapped the paint around a body mounting hole on the underside of chassis away (necessary to make this work) and attached it under the body-mounting screw.
I left a little bit of extra length in the the tether and attached the two locos' tethers together, running the wires under their couplers.
In my case I would never run the calf alone, and the one unit has such poor pulling power by itself it needs a partner to be useful, so the units will stay together - so I did not install a clip to separate them. A person who wanted to seprate them could install a clip as on the tether used by BEEPS, etc. I taped the couplers of this permanently bonded cow and calf together and then wrapped the tape around the wires.
They made a good looking pair.
First, testing them for speed. Here they are on my mainline loop #2, pulling three modern low friction reefers and a heavy scale caboose around 60 inch curves, level track. They are running at about makr number 8 on a ZW-L's throttle scale. The pair can pull this train, and perhaps one extra reefer, around this loop smoothly at this speed, up 2 1/4% straight grades and through 60 inch curves climbing as much as 1%. Anything more and they spin their wheels a bit - well actually, quite a bit if there are five reefers.
Here they are at their lowest smooth pulling speed, an indicated 6.5 on the ZW-L's scale. (At 6 or below, they stop altogether - no lights, no sound). They are running at a scale 18 mph. Remember they are re-wired in series. Stock, their slowest smooth pulling speed was about 32 mph as I tested. About halfway through this test, I halt them with the direction switch, not touching the throttle, and reverse them: note they start smoothly, without problem. Add one or two cars more and they spin their wheels re-starting, etc.
Here is this same pair pulling a train of more cars and higher friction cars - more on them in a minute. They are on my BEEPWORLD loop pulling them up a 4% straight grade. In the first video they stall, spinning their wheels, as they enter a 36" inch turn (level) at the end of the climb. In the second video, they are still spinning their wheels: I just show you the train: those are shortened post-war cars (higher friction) and a MTH bobber caboose. One BEEP will stall at the same place. Two BEEPS won't. So I conclude the WBB 44 tonner has traction limited pulling power just a bit less than a BEEP.
