Author Topic: Atlas Shay with Digitrax DZ126T  (Read 675 times)

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Atlas Shay with Digitrax DZ126T
« on: September 01, 2020, 03:21:49 AM »
I know this isn't exactly a new install as far as the locomotive goes, but I've done a couple of things differently than you typically see so I thought I would post a build thread in case it can help someone else in the future.  I sure learned a lot.

I always wanted one of the Shays.  In one of the towns I model there is an old CP (E&N) station that has a museum display out front consisting of, among other things, a two truck shay very much like the Atlas model.  At the time that Atlas released this loco, a running model wasn't in the cards for me as we had just had our third child.  Since this was a static display anyway, I did the next best thing which was to acquire the parts needed to make a static model.  They are still in a bag. I promise this becomes relevant.

Fast forward to today and over the years I've managed to acquire two more working shay models.  I always had plans to DCC at least one of them and until now, never really felt the need to put it into the production line.  Well then I went and popped for an unplanned Rapido 8-40CM that set me back $260.  So now the plan is to DCC and then sell one of them to raise the capitol! Non DCC Shays have been getting pretty decent returns on eBay lately so I'll see how this goes.

First was research.  I have to give credit to two sources.  First is @peteski 's thread here on TRW:

His attention to detail is awesome and it's always nice to see pictures of the completed project prior to diving in.  Since he did this build the decoders have become smaller which has eliminated the need for his fine construction of the supports but it still inspires and encourages the modeller to think beyond what's sitting in front of them for a solution.

My second research source was a fellow on youtube:

This video is where I got the idea for attaching the motor wires which I'll show later.  It's a complicated step but it really creates a simpler set up to work with.

On with the build.


At first I removed both couplers.  I learned later that you can remove the shell with just one coupler off and man I wish I had.  They are a huge pain to reassemble when they fall apart.

There are four screws in the corners on the bottom.  Remove these and the shell comes off.  Notice that the screw on the front left of the loco is shorter.  Than the others. 

I also left the cylinder assembly on.  This was a mistake.  I managed to damage the linkage from one of the trucks to the crankshaft.  Save yourself the grief and take out the two screws on the bottom that hold the cylinder assembly on.  Set it aside in a safe place as it has no use during the install.

Here is the chassis with the cylinders still on:

The YouTube video taught me that the tender/oil tank assembly is a separate piece from the boiler.  Separating them really simplifies things.  Removing the oil tank also allows you to check for fit prior to final assembly.

My first step of the install was to grind off the lip on the inside of the right of the cab as the decoder goes along this side and that will push it in, contacting the fly wheel.  Next install the LEDs.  I used warm white 0402 SMD soldered to 34awg magnet wire.  I used Bondic epoxy to insulate the LEDs connection prior to inserting it into the metal light housing.  The magnet wires are inserted in to the housing and the LED pulled until its just inside.  Inside the shell I secured the wires to the top with three tiny dabs of Bondic so that they wouldn't get snagged during the reinstall.  Do the same install for the tender llight.

Mine is the original release with the light bulbs and the Mashima motor.  I clipped the light bulb wires off flush with the deck as I planned to replace them with LEDs.  This loco didn't have any kind of light pipe to direct the bulbs' light out the lens so output was pitiful.

The next step was to remove the motor.  The old version has four clips that hold it in.  You can put a small screw driver between the motor and frame and twist, the motor pops right out.

The following step came from the YouTube video.  Atlas used two bronze strips behind the rear motor clip to bring current from the strips that run along the frame, upto the motor contacts.  There is one motor contact on the top of the motor and one at the bottom.  Removing these two strips and soldering directly to the motor contacts allows you to eliminate two points of friction contact, and isolates the motor from the track pick ups at the same time.  It also makes room for both of the motor wires to be brought over to the right side of the decoder using two very short wires which serves to tighten up the install quite a bit.

In this picture you can see the strips removed, the motor support clip and the wires soldered to the motor.   You have to kind of twist the clip to get it off with the fly wheel there but it's doesn't take much muscle and the clips seems to be able to bend quite a bit.  While it's off, round out a little notch in the top of the curve to make room for the wire you will solder onto the top contact.  Orange should be on the top and grey on the bottom.  Even after testing I managed to get it back wards. 

The motor can be reassembled and reinstalled in the chassis.  Bring both of the motor wires out to the right.    I should mention that for these two wires I used solid core wire so I can bend it around things and this case it keeps them away from the worm and flywheel.  In this photo I have attached track pick up wires as well but I wound up removing them and using the wires that come from the decoder.

With the motor back in the chassis, the boiler can be reinstalled.  The grey and orange wires (yes I know I used white) can be bent, stripped and tinned so that they are ready for the decoder.  I trimmed them back so that only about 1mm of wire was exposed.

The first connection to make is the right rail and it can be done now.  I used the red wire.  Cut it short enough that with the decoder in it's place, it bends and contacts the right track pick up.  Solder the wire in place and work it around a little so that decoder rests roughly in the spot where it will be glued. 

At this time the decoder is glued to the chassis with Bondic.  Mount it as close to the rear of the loco as you can.  It also needs to be angled in towards the worm gear to accommodate the decoder's height.  Use just a small dab of glue and make sure the tender shell fits back on.  If not its easy enough to break off and try again.  Once you have the right spot add a few more dabs of epoxy.

Next pull the black track wire over the worm.  Give it a nice bend so that it will hold its shape and not contact the worm.  Trim, trip and tin about 2mm of wire, bend it at a right angle and solder it to the left track pick up.

Now the motor wires can be installed.  Strip and prep them, but prior to soldering, slide a tiny amount of shrink tubing as far back as you can.  then solder, put the heat shrink in place and heat it.  I used the tip of my iron.

Now is a great time to test the loco, which is exactly when I learned that I had the motor wires reversed.

From here you can move onto lighting.  Resistors are required and I like to use large values when I will be staring right at the LED.  in this case I used 10k 1/8 watt.  The power rating of the resistors is way over kill in this case.  I would normally use an SMD resistor, but honestly in this case there is so much room for them there at the side, you may as well use the bigger ones as it makes wire management easier.  I paired them at one end so that can act as the splitter for the common Blue + as well.  they are soldered together but only glued to the outside boiler frame piece so that the main frame can move as needed during reassembly.  Once they are glued in, solder the blue wire to the shared end, and the positive  lead of the Head lamp LED one of the resistors.  Finally solder the white wire to the negative LED wire and shrink tube the connection.

This is another opportinuty to test the loco on the track to make sure the head light works.

After that, temporarily reinstall the cab just make sure every thing is in the right place.

The final step, which unfortunately I didn't take a picture of, is to do the same connections with the rear LED and reassemble the loco. 

The rear two shell screws go back in, then the cylinder assembly ( I had to get a new one from the parts bag - see?!  I told you it was relevant!  Sure am lucky I had a bag of shay parts lying around.) , and finally those awful couplers.

I'm starting to think there room for a sound decoder in there, but that's a challenge for another time!

Have fun playing with your trains.


« Last Edit: September 01, 2020, 04:47:49 AM by craigolio1 »


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Re: Atlas Shay with Digitrax DZ126T
« Reply #1 on: September 02, 2020, 03:25:18 PM »
I don't believe that you put what type of decoder that you used...
Sacramento Valley NTrak


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Re: Atlas Shay with Digitrax DZ126T
« Reply #2 on: September 02, 2020, 03:42:31 PM »
I don't believe that you put what type of decoder that you used...

It is in the subject line of this thread.  :)

Atlas Shay with Digitrax DZ126T

Yes, Craig did a good job squeezing the decoder and large resistors in there.
« Last Edit: September 02, 2020, 03:44:06 PM by peteski »
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