The GP40-2W's are in....

[oakcreekco]

Anyone take any mechanism close ups yet?

[squirrelhunter]

I'll try to post mechanism photos this week, but I can confirm the following:

Atlas GP38/38-2, Atlas GP40/40-2 and the LL/Walthers GP38-2 shells fit on the GP40-2W chassis. So there is now a direct chassis swap to get a short fuel tank that is DCC/Sound ready.

The GP40-2W chassis is going to require a custom made light block if you use another shell on it and not have a "bonfire in the cab"- the GP40-2W shell uses a sloped piece in the cab similar to the Kato SDP40F light tube holder/light block.

The GP40-2W shell will NOT fit on any of the chassis used on Atlas GP38/40 and LL/Walthers GP38-2. The GP40-2W chassis looks to be about 2-3mm shorter. You could file down the ends of the Atlas chassis that is held together with screws or LL/Walthers mechanisms to fit. The Atlas DCC/Sound GP38/40 chassis would be much more work to modify since you would have to account for the retaining clips on the end of the chassis.

[oakcreekco]

Interesting. Thanks for sharing this.

[lock4244]

If these locos are also sold with factory installed decoder,  maybe you got one of those by accident?  It would still work in DC, but the buzzing would be the decoder running the motor?  Maybe?

The other possibility is that your DC pack puts out rectified unfiltered DC (at either 60 or 120 Hz, depending on the rectifier).  Maybe that causes the motor's rotor to buzz (it might have some loose iron laminations).

I picked up a basic Kato power pack. Previously had an old MRC Tech II from the 80's but it's buried in a storage unit.

I'm thinking it's probably the power pack causing the humming, having tested more locomotives it does this with Atlas, Intermountain, and Rapido DC locomotives of various models.

[peteski]

I picked up a basic Kato power pack. Previously had an old MRC Tech II from the 80's but it's buried in a storage unit.

I'm thinking it's probably the power pack causing the humming, having tested more locomotives it does this with Atlas, Intermountain, and Rapido DC locomotives of various models.

That does make sense.  It is likely the hum from the unfiltered rectified voltage from the throttle.  Try powering it with a 9V battery. The battery terminals are perfectly spaced for connecting to N scale track or loco wheels.

Some info on Kato power packs: https://www.therailwire.net/forum/index.php?topic=52560

[lock4244]

That does make sense.  It is likely the hum from the unfiltered rectified voltage from the throttle.  Try powering it with a 9V battery. The battery terminals are perfectly spaced for connecting to N scale track or loco wheels.

Some info on Kato power packs: https://www.therailwire.net/forum/index.php?topic=52560

What is this 9V battery you speak of, lol? See if I can dig one up. Thanks for the link, some good info in there, even if much was above my pay scale.

[peteski]

What is this 9V battery you speak of, lol? See if I can dig one up. Thanks for the link, some good info in there, even if much was above my pay scale.

LOL!  I failed to mention that the reason I recommended a 9V battery is that since it supplies pure DC voltage, there should be no buzz from the motor.  Just to confirm that it is the Kato power causing the buzz.

[lock4244]

LOL!  I failed to mention that the reason I recommended a 9V battery is that since it supplies pure DC voltage, there should be no buzz from the motor.  Just to confirm that it is the Kato power causing the buzz.

I understood that, but been a while since I had a remote or smoke alarm that used a 9V 

Thus far, my little GP40-2W fleet have run quite well on my 5' test track, though they crave the open road. Actually been test running a lot of my fleet since my possessions joined me here in October.

[lock4244]

So I may have added a few more GP40-2W's to my fleet. One of them was 'lights on but no one home', lighting worked but dead motor or no power to motor. Turns out there's brass contacts under the lightboard that were not making contact with the lightboard and thus, no power to motor. Peeled the shell off, removed lightboard and the black plastic used to insulate between chassis and lightboard, and used a small screwdriver to pull the contacts up to better connect to the board. Unit runs fine now.

I've only had one dead out of the box, but imo seems a bit of a weakness in the design. Note the wired pick up from truck to chassis.

Easy fix, but the horns went missing during shell removal. That's two horns I've lost on my GP40-2W's now. This is annoying to me, they seem to fall off pretty easy.

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[mu26aeh]

Motor tab contact issues seem to follow the new design.   Same issue with the old design

[Rossford Yard]

Hopefully, Paul Graf still checks in here....

Please do this IHB scheme in N.  I would move my IHB layout era from 2000 to 2010 to accommodate.....I'm sure my promise to buy all road numbers you produce will be enough to move this scheme forward in the next batch.....thanks in advance.

[Ed Kapuscinski]

Motor tab contact issues seem to follow the new design.   Same issue with the old design

It's a real bummer too. I had a similar experience with a GP35 too. Same fix as well.

[mu26aeh]

Hopefully, Paul Graf still checks in here....

Please do this IHB scheme in N.  I would move my IHB layout era from 2000 to 2010 to accommodate.....I'm sure my promise to buy all road numbers you produce will be enough to move this scheme forward in the next batch.....thanks in advance.

Nope, hasn't officially visited site for almost 2 years.

[peteski]

Nope, hasn't officially visited site for almost 2 years.

Yes. Not sure if Paul is simply too busy to visit TRW, or we drove him away somehow.
There is another Atlas employee here.  I think his user name is GP38 (or something like that).

[lock4244]

Motor tab contact issues seem to follow the new design.   Same issue with the old design

It's a quick fix, minor issue. I've not had a similar problem with an Atlas four axle before, so haven't had to remove a shell in some time... and they sit in boxes in storage so no maintenance required.