Rocket Surgery on the PRB brass ATSF 3400 Pacific

[mmagliaro]

Update as of now - first, I got the new drawbar fabricated from brass and got it tested with the stock trailing truck.   I 'think' it's going to work.   Photos coming.

But even after reassembly, pickup remains the problem, even with the stock tender trucks polished up for better contact, it constantly stalls.  I can see why Ron got frustrated.   You'd think with all that weight and contact points it would be bulletproof, and it is anything but.

And I got Derk's (ATSF Models) tender trucks in - made it here OK, and look good.  More rocket surgery on the tender.

I added a spring under the head of the screw that holds the trailing truck to the frame, and a PB thin washer between
the truck tongue and the frame, so that the contact from that truck to the frame actually works.
I also changed the pilot truck and tender truck springs to slightly stiffer ones to get better contact, and I hard-wired
the tender across the drawbar to the motor (this was all non-DCC, and without putting all-wheel-pickup trucks in the tender).
After that, it was darn reliable.  Getting good pickup from the pilot and trailing trucks was key.

[randgust]

Got the trucks in, and did what I knew was coming - ground off the original tender brass tender bolsters, made new ones out of .040 styrene, drilled and tapped.  The truck centers were completely different.

Had to make new bolster bearings on the trucks out of old Atlas worm bearings, a precise fit so perfect I could just 'plain old' 00-90 screws to hold on the trucks.

So I patched together all the pickup wires, tied them into the temporary wiring harness (remember this will eventually be DCC) and did some test running.   The trailing truck is in place along with the new brass drawbar, now the new tender trucks - and wow...... just wow.  THAT fixed the pickup problem.   I'm back and forth through my crossovers and everything else with no hesitation.

So far, so good.  I've got to do full performance testing before I convert to DCC here, next on is the pilot truck as rebuilt.  The spur gear bearing repair looks fine too.   Biggest surprise is that there 'aint no way' to put the tender body on now, the trucks block the original screw holes, and taking the trucks off requires unwiring.... so I need a different way to hold on the tender body, I'll come up with something.



Link:  http://www.randgust.com/PRB342911.jpg

[nkalanaga]

Magnets?

Unless you pick it up by the tender body, does it have to be held on at all?  The truck look wide enough that you could pick the tender up by grasping them, under the body.

[randgust]

OK, here's a question.    Any tips or ideas on mounting the speaker into to the all-brass oil tender on this?

Unlike a coal burner, I can't do what I did on the decapod - cut the coal pile out, put the speaker there, and cover it with black foam (worked great).

I can't go through the floor.  The center part is already covered in heavy soldered-on weights and a new slot cut in to bring up the hard-wired truck wires in.

I don't know if it's advisable to put the speaker DIRECTLY on the brass body (using it as kind of a baffle box), or put it in a baffle on speaker and mount that in the tender.....

I'm considering drilling holes in the front wall of the tender (behind the cab) that's the least visible location I've got and it's visually screened by the cab.   Or mounting the baffle box in a hole cut there.   I'm using the Tsunami mini-cube speaker and parts.   Very satisfied with the sound on my Decapod with the same rig.

[nkalanaga]

Another suggestion for mounting:  If the inside sides of the body are available, 2 pieces of brass angle soldered in the middle, with holes in the floor between the trucks, would allow screw mounting without the trucks getting in the way.

[randgust]

Dirk's trucks have interior paired truck wires to handle both sides of both trucks.   I cut a slot between the two big weights here to bring the wires up and so they can rotate without binding.  So between the big trucks, truck wires, and those big soldered-on brass weights (you'd about melt the tender getting those off) there's no room above or below the truck centers.  Normally that's a good approach, won't work here.  And I usually go for the coal pile.

I can mount it directly to the body (it's a big body) but don't want visible little holes, wondering if that alone is enough of an echo chamber without drilling but I have no experience.  Not sure if would be muffled or metal tin sound.   Still leaning toward drilling out the front of the tender wall and cutting a speaker-sized hole there behind the cab.   Any other holes would be visible.



Link:  http://www.randgust.com/PRB342903.jpg

And I'm jamming in the Tsunami decoder, wiring harness, headlight resistor, a detachable TCS 2-pin plug for the speaker.  I got it all in a Trix tender.

[randgust]

I think I got it.    It's hard to see in that picture but the tender is held on to the frame by 4 screws up from the body into an "L" brass channel running the length of the tender on both sides, inside.  It's soldered into the body, and drilled and tapped for the 4 screws accessible from the bottom, only if the trucks are off.   I tried to solder in a clip shaped like a Z, that failed.

I cut a short chunk of the "L" (with the screw hole in it) off with an abrasive disk, just in front of the screw hole, removing the hole part with a piece of the brass channel.   I rebent that into a "Z" shape, with the tapped hole on the base, and made it into a clip.   Screwed it back on the tender base so that it turns into a clip on the remaining channel and is adjustable.

Then you can just slide the tender body on the frame by pushing it toward the front and it locks in place.  By some adjusting of the screws and rebending I got this to a nice hard 'click'.  Since the only way to get in the tender to put the six pin plug together is to get the body off the frame, and taking the trucks off to get to the body screws won't work (plus those fragile pickup wires now on the trucks) the body had to be removable when it is sitting on the track.   What a puzzle.

Gave it a test run, works well, and there's enough 'slop' on the 6-wires that nothing hangs or derails, and the drawbar replacement appears to work.  And the lead truck doesn't derail, but darn, it still shorts out on a LH curve of 11", so more of the inside of the cylinder has to be ground off.   Getting there.

[dnhouston]

Very creative solution.

[peteski]

I applaud your perseverance for getting this loco to run on 11" curves it was never meant to traverse.