Atlas Classic GP-35 #46505 MRL #401 Conversion To DCC

[digitaldave]

I have acquired an Atlas Classic GP-35 #46505 MRL #401, and was wondering if it could be converted to DCC, so I contacted Atlas. They replied that by default, it's not compatible with drop in decoders, but there may be one that could be soldered in (they mentioned TCS). So I had a look on the TCS web site, and it looks lile their ASD4 decoder may indeed be compatible...

Does anyone know for certain if the TCS ASD4 is compatible with this loco, or if there are any other alternatives (from TCS or other manufacturers)?

Thanks,

Dave.

[daniel_leavitt2000]

Use the TCS CN:
http://tcsdcc.com/1278

Unlike other wired decoders, these will not require extensive milling of the frame. You may need to file a small channel along the top for wires (I didn't need to in my installation) and a small channel down into the motor cradle.

You can also buy DCC ready frames from Atlas:
https://shop.atlasrr.com/p-4011-n-gp-30-35-mainframe-left.aspx
https://shop.atlasrr.com/p-4012-n-gp-30-35-mainframe-right.aspx

This makes a very quick and solder free installation. You might need to extend the bronze motor contacts. This allows you to use less expensive NCE and Digitrax decoders.

[Jbub]

Use the TCS CN:
http://tcsdcc.com/1278

Unlike other wired decoders, these will not require extensive milling of the frame. You may need to file a small channel along the top for wires (I didn't need to in my installation) and a small channel down into the motor cradle.

You can also buy DCC ready frames from Atlas:
https://shop.atlasrr.com/p-4011-n-gp-30-35-mainframe-left.aspx
https://shop.atlasrr.com/p-4012-n-gp-30-35-mainframe-right.aspx

This makes a very quick and solder free installation. You might need to extend the bronze motor contacts. This allows you to use less expensive NCE and Digitrax decoders.

My curiosity is peaked here. Do you know or does anybody here know if the LL gp60 body will fit on this or a similar frame? If so that would make for a much simplified dcc sound conversion from the non dcc friendly LL frame.

[daniel_leavitt2000]

The latest GP60 run had a DCC ready frame. But parts from Walthers are not available. I have not looked into using FVM GP60 frames with LL components. I believe LL used larger worm bearings than Atlas uses. The motor cradle might not fit either.

That being said, I believe that LL and Atlas GP trucks are interchangeable (though not mechanically identical). I have to check but FVM, IM, Atlas and possibly MTL Blomberg gear cases are identical.

[digitaldave]

@daniel_leavitt2000 thanks very much for the reply. Good news either way, to be honest I hadn’t even thought about changing the frames!

[Ed Kapuscinski]

Use the TCS CN:
http://tcsdcc.com/1278

Unlike other wired decoders, these will not require extensive milling of the frame. You may need to file a small channel along the top for wires (I didn't need to in my installation) and a small channel down into the motor cradle.

You can also buy DCC ready frames from Atlas:
https://shop.atlasrr.com/p-4011-n-gp-30-35-mainframe-left.aspx
https://shop.atlasrr.com/p-4012-n-gp-30-35-mainframe-right.aspx

This makes a very quick and solder free installation. You might need to extend the bronze motor contacts. This allows you to use less expensive NCE and Digitrax decoders.

Wow. I don't know why I never thought of this trick before! Converting my RS3 just got a LOT easier. Thanks!

Lol, j/k. Just realized even the new ones aren't DCC friendly. Oh well.

[Steveruger45]

@daniel_leavitt2000 thanks very much for the reply. Good news either way, to be honest I hadn’t even thought about changing the frames!

You could even put sound in these. Frame milling is needed and would be about the same in either the non or dcc ready frame and is a wired install.. Like this https://www.therailwire.net/forum/index.php?topic=44564.msg573635#msg573635
If your ok to do some soldering and don’t want sound I would consider the wired lokpilot micro for either non or dcc ready frames.  On the dcc ready frame you could use the slide in lokpilot micro but you would have to file away a bit of the frame at the top above the motor and some soldering of short wires between the motor contacts and decoder pads may also be needed in this case.

[cjm413]

My curiosity is peaked here. Do you know or does anybody here know if the LL gp60 body will fit on this or a similar frame? If so that would make for a much simplified dcc sound conversion from the non dcc friendly LL frame.

GP60 has a longer distance between truck centers than GP38/39/40/-2

[Rich_S]

Atlas GP35 using the TCS CN decoder




Walthers / Life-like GP38-2 with TCS CN decoder.

[GM50 4164]

This is how I go about doing my installs with these older frames. Yes the TCS CN and CN-GP's are nice to work with but using a Digitrax DZ126 allows me to save quite a bit on price between the two brands. Not a lot of milling is required to make either work. I like to swap the sickly yellow LEDs for some golden or sunny white ones though.

[jdcolombo]

Almost any tiny motor decoder can be used in the same way that Rich S did.  In addition to the Digitrax DZ126, the ESU LokPilot Micro V4, the ESU LokPilot Nano, or the Zimo MX616 Nano; MX617; MX621 or MX622 should all work.  The ESU and Zimo Nano decoders are incredibly small, will fit under nearly any stock light board, and will provide the best motor control and lighting effects in the industry.

Doing the install this way keeps the original light boards, which often provide the best electrical connection for a decoder.  Cut the traces to the LEDs; use the light boards for power for the decoder; then wire up the LEDs separately using the decoder's blue, white and yellow wires as Rich S did.

John C.

[peteski]

Doing the install this way keeps the original light boards, which often provide the best electrical connection for a decoder.  Cut the traces to the LEDs; use the light boards for power for the decoder; then wire up the LEDs separately using the decoder's blue, white and yellow wires as Rich S did.

John C.

Replacing the stock 270 ohm LED resistor with one of a higher value (like 680 ohm for yellow, and 1000 ohm for white LEDs) would also be recommended.  The 270 ohm resistor is IMO a bit too low for DCC where the voltage will be constant 12V or more. The original resistor seems to be designed for optimal headlight (LED) brightness when running the DC loco at a lower voltage. After all, not many people run their DC models at full throttle all the  time.

[k27463]

This is how I go about doing my installs with these older frames. Yes the TCS CN and CN-GP's are nice to work with but using a Digitrax DZ126 allows me to save quite a bit on price between the two brands. Not a lot of milling is required to make either work. I like to swap the sickly yellow LEDs for some golden or sunny white ones though.

I've done this with a few.  It's really not bad.

I -did- end up cutting down the light boards and only using them for power pickup, and I'm using SMD LEDs for headlights mounted to the shell 

[jdcolombo]

Replacing the stock 270 ohm LED resistor with one of a higher value (like 680 ohm for yellow, and 1000 ohm for white LEDs) would also be recommended.  The 270 ohm resistor is IMO a bit too low for DCC where the voltage will be constant 12V or more. The original resistor seems to be designed for optimal headlight (LED) brightness when running the DC loco at a lower voltage. After all, not many people run their DC models at full throttle all the  time.

Agree.  And replacing the horrid yellow LED's with warm-white ones isn't hard, either.  Desolder the old ones, solder in new ones. 

I've found over the years that if you can stick with the original light boards, that's the best guarantee of good electrical conductivity.  After-market boards often tend to be too thin, resulting in poor electrical contact.  I had that problem with at least one TCS split decoder I tried in the past.  Plus, both the ESU and Zimo decoders will run rings around anything else out there in terms of motor control.  Zimo is the winner by a hair or two, but either will beat the pants off TCS or Digitrax, IMHO (if you care about REALLY slow speed smoothness).

John C.