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writing this while I have the time. Pics to follow!

I always liked the MTH and the Atlas MP15AC model switchers. I missed out on the Atlas and I run everything thru DCS so that's the engines I bought. Trouble is that all MTH RK models are 3 rail only. I considered swapping parts between the brands but never attempted it. I bought a couple of older Atlas 2 rail switchers and there's another story...

Sometime back I got my hands on a pair of MTH 3/2 2 axle trucks. At that time I didn't know what engine they had come out of. I put them on the shelf for future use. Our grandson inspects everything I do or will do in the future. He found the box with the trucks and asked what they were for. After telling him about the several MTH switchers that would get converted someday, he told me that day had come! He also decided we would 2 rail the newer PS3 SW1500 against my better judgement.

So with all the other projects going and ones waiting in line for attention, this is now my project. I got the trucks out and searched for how to connect power. I couldn't get any results from the MTH product locator for parts as it appears to be down again. I was thinking the trucks fit a GP style engine. Searching around the basement and comparing trucks, it appears these extras maybe from a U25B? or similar 4 axle MTH engine. I was surprised that each model I have may have different trucks.

So I made some mistakes comparing the stock trucks to these thinking they were the same, just set up for 2 rail. They aren't quite set up fully or correct. I got lucky in that they will work. For some reason each truck is different slightly. The lead or front truck (marked with a F sticker) had a removable three rail coupler tang! That will come in handy later for clearance body mounting couplers. The other "R" truck has that tang casted as part of that truck.

I also found out quickly that I didn't get any power transfer. To the point, there's no plunger assembly getting power from the wheels to the hot leads. They have 2 rail wheels but are actually set up for 3 rail! The red wire leads were dead. They were connected to where the roller pick-ups would be mounted in 3 rail.

With no parts available right away, I made my own plunger assemblies. I cut 2 short lengths of solid #12 copper wire  a little longer than needed and soldered flex leads onto the sides of them. I slid them into the correct place so that they touch the trucks bushings on the insulated sides. I made a rectangle out of plastic and drilled two holes in it. One is for that wire lead and the other is where the mounting screw goes thru. I had to cut side notches to allow the motor mounts to fit by. I tighten down these plastic pieces to put tension against those solid copper wire pieces inside the trucks.

I put them on the engines and quickly wired it up. I made a mistake and didn't realize that one truck is reversed. After popping a breaker to the track, I rewired so that the pick-up wires on the front truck are reversed. Wham! It runs!!!

Next, fixing pilots and mounting couplers. I'm going to attempt using the Atlas electro couplers again, this time on this model. Our grandson wanted a dedicated yard switcher and I guess the four (road engines) I already have aren't to his liking.



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Last edited by Engineer-Joe
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Now for switcher #2! Yes, I know... I still haven't finished the first one. I made a pilot and it was a fair amount of work. So I'm making a mold of it out of silicone and it's taking a long time to dry. So I started #2.

This should be an easy one. It's a MTH PS3 South Buffalo RK S2 switcher that's already 3/2 convertible. Yeah right.....

The first thing here is that one truck is closer to the end than the other. So that's a good clue. Ends up that unlike my other MTH 4 axle diesels, this one has two identical trucks facing the same direction. More on that to come.

Removed the trucks to get at the stock 3 rail couplers and pilots for removal.

So my attempt to mount the pilots that a forum member gave me, started off OK. I had to drill the cast frame to accept small metric screws. Got the first one mounted by luck.

Started the second one and noticed that the truck's sideframes hit the pilot? Started grinding the rear of the new pilot, then the truck's tab, then the pilot some more! Became apparent that the offset is different. Still didn't identify fully what was going on. Got the second pilot mounted and went on to the wheel swap.

I have a few sets of 6 axle wheels right here, so I grabbed a set. Swapped out the first truck carefully using the wheels with the insulated bushing near the gears.

Started on the second truck and that's where it got interesting! The wheel sets match the other truck? That's a problem because normally they are reversed.

To skip ahead I found that I needed to take 2 axles apart, and reverse the bushings to get them oriented correctly. I slid an axle into a large crescent wrench and snugged it down against the plastic insulator. I then used a drift and hammered the axle downward while supporting the wrench. Reversed the bushings and put it back together. I laid the wheel face down on the flat bench and drove the axle back in until I got the correct wheel spacing of near 1.110 to 1.118 I believe? I measured a few MTH engines to come up with that. They run well on my layout so that's what I went with.



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Darn 3/2 switch burned me again!

I made a long draft (post) here about how I thought the wiring was wrong to the switch. I finally drew a diagram and realized it should work as wired?

So after taking the engine apart and making a post that I deleted anyways, it's solved. I rocked the 3/2 switch around a dozen times total to get it to work. I had it once sooner and realized it didn't connect for long.

Funny how something works on the bench and when you carry to the layout, it quits.

Now the SB Alco S2 runs. Wasted the whole morning, but it works.

I tried to make a mold and cast a second pilot for the last several days. I got bad silicone, bad resin, etc. I finally gave up. Our grandson was over last week and asked why it was taking so long? He's good at ordering me around. He just doesn't help much yet.

I spent all morning modifying the floating pilot and making a shim for it. It ended up much too low!

So I just threw on the old pilot and mounted the Atlas electric couplers. Wasted time! Urrggg!



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You state on your posts "why go back to DCC when I have DCS".    I think the reason became obvious this summer.    The sole provider of DCS is closing up shop and the support and development for the system may go away.

On the other hand, there are at least nn major suppliers for DCC so if one goes under, general support and development continue.    Mfg I can think of are Lenz, Digitrax, Northcoast Engineering, CVP, and MRC that make complete systems.    There are a couple of others in Europe too, I think.   And there are some around such as SoundTraxx and QSI that make only receivers.

I have been very cautious about MTH and to some extent Lionel providing proprietary systems that are not licensed to other mfg.

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