746w tender issue

If you suspect the tender center rail pickups, there are a few things you can do:

Lubricate/Clean - The rollers rotate around a pin and it can get grungy due to age, old lubricant, rust and so on. I find that using Goo-Gone can break up the crud. I then follow up with CRC 2-26 to clear any further remains and as a fresh lube. Also make sure the wheels don't have a build up of grime. Goo-Gone will break it down. Wipe it off and apply some oil to the intersection of the axles and wheels.

Spring Tension - The spring can become weakened due to age, use, and abuse. Depending upon your abilities, you can replace only the spring, the pickup assembly, the coupler plate, or the truck as a whole.

Physical Deformity - Sometimes the truck is physically deformed, or the pickup assembly's plastic locating tabs have broken off or melted and so on and so on. Inspect carefully and remedy as applicable.

External Issue - The issue may not be the tender at this point a few things to look at, especially if other pre/postwar air whistle tenders exhibit similar symptoms (you can/will test another, right?):

• Dirty Track - clean with Goo-Gone
• Weak Transformer
  • Transformer too small for the total load
  • Transformer is of a model that does not have the 5V whistle boost circuitry
  • The Whistle control contacts need to be cleaned
  • Weak rectifier - replace with new rectifier or diode

I know that the above is a dump of lots of potential places for gremlins to hide, but I hope it helps you figure out where your troubles lie.

Thank you for the detailed response. After inspecting and cleaning everything else, and then seeing what you wrote, the part about spring tension is where my attention keeps going. It does seem like they’re weak and the rollers aren’t making good contact once the tender is moving. I’m going to first try and clean and lubricate them and see what that gets me. My track is pretty clean, as I clean it by hand and with the postwar track cleaning car. I’m using a postwar ZW to power my layout, and I don’t think it’s that because this is the only tender I have had an issue with. I’m going to focus on the rollers and springs first to see what I can do. I’ve learned a lot about repairing these things, but I’ve never tinkered with the springs. Is it a tough job?

@James B posted:

I’m going to focus on the rollers and springs first to see what I can do. I’ve learned a lot about repairing these things, but I’ve never tinkered with the springs. Is it a tough job?

Well..

@bmoran4 posted:

Depending upon your abilities, you can replace only the spring, the pickup assembly, the coupler plate, or the truck as a whole.

Let us reference this parts exploded view:

Replacing the Spring (only) - Some claim this can be done by unraveling the old TCL-45 spring from around the mounting TT-234 rivet and installing the new one the same way, kinda like a key on a key chain. To some, this is desirable because it doesn't require any special tools, soldering, or riveting. While you can damage/cut off the old spring to make removal easy, installation with this method can distort or damage the new spring. Good news is the spring is cheap, so you buy a bunch and build up your skill.

Replacing the Pickup Assembly - You remove (drill out) the 480-19 rivet releasing the existing 481-6 pickup roller assembly. Access to do this operation requires removal of the 482-3 or 481-10 coupler base plate which is held on by metal tabs wrapped around the axles. You carefully bend the tabs minimally to release the plate or you can gently spread the bolsters to drop the axles out releasing the base plate. The tabs can break, the bolsters loosen, and the repair quality can suffer. You also will need to de-solder the pickup wire or cut it off from the existing pickup assembly. Now, you take your new 481-6 pickup roller assembly and use your new 480-19 rivet to install to the base plate. This requires a rivet setting tool such as Brakeman's Riveter or the Arbor press with the appropriate Lionel or Hobby House dies. Yeah, a punch may do it, but not as cleanly and nicely. Solder the pickup wire to the pickup assembly and reinstall the base plate.

Replacing the Coupler Base Plate - Just like above, you release the old base plate by bending the metal tabs, but since you have a new 482-3 or 481-10 base plate, it doesn't matter if one or more of the tabs break off. Use pliers to bend the tabs of the new base plate around the axles.

Replacing the Truck - Replacing the truck as a whole works well. I believe the 746W tender uses the 482-1 truck in the front and the 481-1 in the rear. Remove the shell and loosen the whistle from the frame to gain access to the truck studs that are held in place with the 480-18 horseshoe clips. Use pliers or a screwdriver to remove the clips to drop the trucks out. Be sure to order new 480-18 clips in the event the existing one are mangled on removal. De-solder or cut the pickup wires from the old pickup assembly. Solder the wires to the new trucks and install the trucks to the frame with new or reused 480-18 clips. Refasten the whistle to the frame. Reinstall the shell.

I generally go with the last two repair methods as the parts are inexpensive enough compared to the time it takes and risks of getting stuck due to causing more damage.

I would replace the entire truck assembly before screwing around with the springs, simply to avoid the frustration of a bunch of springs getting mangled trying to wind them around where they go. Trying to track down the entire wheel assembly should be interesting. I’ll check on the ‘Bay first. Sometimes it’s cheaper to buy a full caboose and use the wheels rather than buying just the wheels. My suspicion is that the rollers and springs are shot

Update: the springs are completely shot, especially one of them. It’s totally compressed to the point that I didn’t even see it at first. So that seems to be the problem. The rollers aren’t grooved, and they seem pretty clean. Very, very slight wear and pitting on them but I’ve seen, and run, much worse. I think the springs are what’s causing the issue. Gonna attempt to put them on manually as suggested

Update, Part 2:

I was able to manually put on those springs. That’s easily the most difficult repair job I’ve done! I had to clip the pickup wires and remove the truck assembly, and remove the truck plate to get access to the stud where the spring goes, and they don’t go on easy, but….IT IS POSSIBLE!