UP 4-8-4

[RailMan]

I have a older UP 4-8-4 and as some of you know the pancake motor was re powered with a can motor. I really would like to keep the shell and replace the Chassis w/Motor (Niagara). Does anyone know if my old UP shell would fit the new chassis. Looking at the pic it appears it would but I really not looking to buy it unless I was sure. This of course is a Bachmann loco.

[Jim Banner]

If memory serves, the pan cake motored Northern was replaced by the Bachmann Plus Northern - same shell, upgraded mechanism with can motor, flywheel, and worm drive.  Some time after the mold broke, the Plus version was replaced by the Spectrum version - new shell, new mechanism.

If you are looking for an easy upgrade of a pan cake motor version, try to find a used Plus version.

Jim

[ACY]

You can probably find a used Bachmann Plus 4-8-4 for about $40 on ebay. It will do you no good to buy the newer DCC version because the shell will not fit without a lot of modifications, unless you enjoy making such modifications then by all means do that.

[RailMan]

Thank you guys for your reply's, I will have to look for the plus ver on ebay. What year did they convert from the pancake motor to the plus can motor.

[r0bert]

THe old version of the UP 4-8-4 was the Santa Fe Northern in UP paint with a vandy tender.
The new version uses the NYC Niagra in UP paint.
If you go to buy replacement loco for upgrade parts, you'll need the ATSF version, and I would get the newest DCC on board version, as it's really a great running unit.
Bowser made a repower/upgrade kit for these for years, and though discontinued, they shouldn't be too hard to find.

edit for additional info;
looking at the current DCC version, see diagram
http://www.bachmanntrains.com/home-usa/dwg/dwgs/H508X-IS001.PDF
the actual loco shell should fit without much if any modifications.
The more difficult part may be fitting the electronics/DCC boards into the vandy tender and retrofitting electrical pickups onto the tender trucks, but both can be done.

[r0bert]

New version


old version


side by side

[r0bert]

old chassis looks the same as new ATSF chassis except for motor type and new DCC version does not have smoke pot.

see diagram referenced above
inside of shell

[RailMan]

Thanks Robert, that was a big help, I really appreciate it. One more question, I am not running DCC only DC, does the engine need power from the tender or will the engine run with out it. It's no big deal to power the trucks for a p/u but I was just curious.

[r0bert]

The new drive picks up power from both the loco and the tender, but that power is routed thru the tender circuit board, and back out to the motor and LEDs seperatly.
In the loco there is no direct connection from the wheels to the motor or LED, so if you were to set the loco only on the track without being connected to the tender circuit board, it would not operate.
The loco can be rewired to eliminate the circuit board in the tender by routing the pickup wires directly to the motor, but a resistor is required to lower the voltage for the LED, and would need to go into one of the LED lead wires.
The loco will operate without tender wheels picking up power, but the more wheels picking up power, the better.
Since you are running DC only, you can unplug the DCC decoder from the circuit board, and replace the decoder with the included jumper plug.
One last thing, and I could be wrong, but I do not think, or remember, that Bachmann ever produced a can motor version of the ATSF northern, in the Plus or Silver Series lines, only can motor version is the current DCC on Board version. 

[RailMan]

OK, Thanks Robert. This gives me food for thought. I will have to wait and get the chassis then decide what the best recourse is.
Thanks again
Al

[r0bert]

any time, if you need more help, just let me know.