Does Atlas/Kato GP35 Need Frame Milling to Fit a Decoder?

[rrjim1]

The extra pulling power is worth the effort to learn how to install hard wired decoders.
To install a DZ123 in my "old" GPS I think I re over 3 grams of material.
With the newer DZ126T you may be able to remove less.

Only if you need the extra pulling power, I went with a long 1% grade so I don't need it. Two new Atlas GP35s don't have a problem pulling,  (what I consider a normal train on my layout 30-40 cars). up and over the 1% grade. Also with the old Atlas/Kato you get the crappy old high speed motor instead of the new modern scale speed motor. 

[randgust]

I just wanted to bring that up as probably the only valid reason to reconsider, and it purely depends on what you'll be expecting a locomotive to do on your layout.   I'm stuck with long trains and steep grades, sure matters to me.  But in the evolution of N over the last 40 years, it's one of those few changes that's not be entirely positive.

[Rich_S]

Kisatchie, If I can install a TCS CN decoder into one of these Atlas / Kato GP35's, anybody can. I used an X-ACTO Razor Saw and a Stanley metal file to modify my frame, all on my portable work table. 

Here are the photos of my install:







I highly recommend using Kapton tape to insulate the motor caps and any other location where you feel the decoder board my touch the frame.

http://www.kaptontape.com/1_Mil_Kapton_Tapes.php

When you put the frame halves back together, do not over tighten the screws, too much force and you will strip the plastic bushings, as we always said, finger tight will do.

Do you have a good pencil point soldering iron? I prefer Weller irons and I purchased mine through Micro-Mart.
http://www.micromark.com/economy-priced-variable-temperature-soldering-iron,9257.html

Lastly, my eyesight is not as good as it use to be, I also recommend a Optivisor
http://www.micromark.com/optivisor-binocular-magnifier,6711.html

Like I said, if I can do it, anybody can, just take your time and you'll find out it's not that bad.

[Kisatchie]

I have an offer from a forum member to do the decoder add, so I won't be doing the work myself (whew!).

Thanks for the encouragement though.


Hmm... razor saws and
Kiz...? you're looking at
some loose fingers lying
around...

[mmyers]

My first decoder installation in 1996 was in an Atlas/Kato GP35. It required cutting to fit the DN93 decoder. Should be much easier now that decoder are so much smaller. That reminds me one of these days I need to install more modern decoders in them.

Martin Myers

[rrjim1]

With all that unnecessary frame removal you going to lose a lot of that extra pulling capacity. Really one only need to remove very little fame material for this install and hardly any tape. I use more tape to hold the wires down into the groove I mill into the top of the frame so it looks nice and neat.   

[Kisatchie]

The auction for the GP35 is over, and I didn't win. So one problem less LOL.


Hmm... that's what Kiz
thinks...

[rrjim1]

The auction for the GP35 is over, and I didn't win. So one problem less LOL.


Hmm... that's what Kiz
thinks...

I don't like auctions, I hate waiting, I would rather just find a decent price with Buy it Now! 

[Viperjim1]

I've had and still have some of the Gen 1 matos but changed to n. Scale of Nevada or digiframe milled chassis, just sold the last of them on fleabay.

[ns737]

if you are putting a decoder in. the motor speed is matched to other engines. so high and scale speed do's not matter.

[rrjim1]

if you are putting a decoder in. the motor speed is matched to other engines. so high and scale speed do's not matter.

It sure matters to me, I don't want to speed up my great running locos just so they can run with crappy ones that have a high speed motor.   

[peteski]

It sure matters to me, I don't want to speed up my great running locos just so they can run with crappy ones that have a high speed motor.

You know Jim, speed matching works both ways. You could reduce the speed on the fast locomotives to match the slower ones. 

[rrjim1]

The high speed motor starts at a much high voltage than the scale speed motor. So if you set the voltage lower for the high speed motor the high speed motor will not start.
There is a huge difference in the motors, there both 12 volt DC motors, the high speed one is a 30,000 rpm motor while the scale speed one is a 13,000 rpm motor. 
In my experience the high speed motor just won't run as smooth, and doesn't have as much torque at the lower rpms as the new scale speed motors.
If there is a way to get a high speed motor to run as slow and smooth as a scale speed one I sure would like to know how!     

[ns737]

I have many times. I run atlas and kato just fine. they run smooth.

[peteski]

If there is a way to get a high speed motor to run as slow and smooth as a scale speed one I sure would like to know how!   

Install a DCC decoder and mess around with either 3-step or 28-step speed table, kick-start value, and BEMF settings.  That is why it is so much easier to speed-match DCC locos than it is DC locos.  It is not painless, but it is possible.  It won't be perfect either, but close enough for smooth operation.