Tender for Model Power/MRC 4-6-2 / 2-8-2

[nickelplate759]

So ... I picked up a new production Model Power/MRC 4-6-2.  It doesn't have DCC+Sound installed.  I want to make an NKP Pacific out of it. There are a few things to do, but the first things relate to DCC and thus the tender.    It needs drop-equalizer tender trucks, and could use better power pickup.  The desired tender should resemble a USRA medium tender, possibly with an extended coal box.   I have a Bachmann tender off a light 4-8-2 that has the right trucks and the right shape.  As I see it my options are:
1. Substitute the Bachmann tender for the Model Power tender:
   Pro - the Bachmann tender looks better and the trucks already fit.
   Con - the tender drawbar is very different from the Model Power tender and will take substantial rework.
2. Fit the Bachmann trucks to the Model Power tender
  Pro - the drawbar won't need to be changed
  Con - the Model Power tender isn't nearly as nice, and the truck pickups will probably have to be hard-wired.
3.  Substitute a Kato USRA tender and somehow get the Bachmann trucks to work
   Pro - It's a Kato, and nice, but not really nicer than the Bachmann
   Con - both the drawbar and the truck-based power-pickup will need work.

Does anyone have experience with a similar conversion?  The trucks are interchangeable with regular Bachmann tender trucks, so that's not the hard part.

[brokemoto]

I am not a DCC user.  I have swapped out the factory tender on the eight wheeler, mogul, mikado and Pacific.  I  have swapped in the Kato on the mogul, the B-mann on the others.

The first thing that you do is remove the B-mann drawbar, then replace the front truck.  For some reason, unless you want the tender to sit funny, you must fashion a washer out of styrene for the front truck.

Your next task is to remove the wires from the MP tender.  I remove them at the solder point in the tender.  You then separate the tender and locomotive.  You leave the drawbar on the locomotive.

The next step involves a test fit.  Pop the shell off the B-mann tender,  Put the locomotive-cum-drawbar onto your workbench then push the tender up to it.  Get it as close as you can without its lifting the drivers off the workbench,  Center the drawbar and mark it. 

Get out a set of pin vises and a Micro-Trains coupler screw.  (You must have at least fifty-eight of those things in your parts box).  Tap a hole with the appropriate size pin vise where you marked it.  This is a bit of a slow process, as you do not want to break the pin vise.  Take your time, take care, if your joints start to ache, take a break.

Fashion a "washer" out of a piece of styrene.  It really does not matter what size it is, as long as the measurement across it is greater than the measurement across the tender end of the drawbar.  This is to prevent the drawbar's riding above the top of the MT coupler screw and popping off its post.  Screw the screw through the "washer".  Screw the screw into the hole that you tapped.  Again, take your time lest you bend the screw or strip the head.  If you do either (or both), simply back out the screw with a pair of needlenose pliers, get out another screw and start again.

The tender end of the drawbar is a clip.  Simply clip it to the screw.  The separation that you get is about the same as the factory rigging.

Another thing that I have found necessary, to accomodate the wiring, is to cut out the panel below the ledge (I assume where the fireman would stand to shovel coal).  I keep the ledge, but cut out a slight opening, only as wide as the coal doors,  below it.  You can not see it when the locomotive and tender are running.

I have not had a problem with drawbar's coming unclipped from the post.  My passenger trains average four passenger cars and two express cars.  I have pulled six and two express, just to see what it would do.  I had no problems with the drawbar's coming unclipped then, either.  These are mostly MT cars, with a few WOT, Kato and RR cars, as well.

If you are feeling really creative, and, if you can find the appropriate details and short four wheel trailing truck, you could bash a NYC&StL Hudson.  Those things were little more than a USRA light Pacific with a four wheel trailing truck.  I have seen only one or two photographs of those things, and at first, I thought that it was a USRA light Pacific or a copy.  Then, I saw the four wheel trailing trucks.

Please let me know how it works for you.

[nickelplate759]

Thanks for the detailed write-up, brokenmoto.  The procedure you describe is similar to what I did to attach a Rowa tender to a 2-8-2.

[nickelplate759]

Related question:  I picked up an MRC 2-8-2 with sound.  I want to swap the tender SHELL (only).  The original shell has the speaker fastened to is somehow (under the coal load).   Can I just carefully pry it out (i.e. is it glued in somehow)?

Maybe later I'll put a better speaker in, but for now I really want to swap shells.

Also- what's the best way to get the cab (only, not the boiler) off of this beast?

[never mind] The speaker is glued to a foam baffle that is glued to the bottom of the coal load.  Best way would be to remove the coal load (it's a snap fit) from both tender shells and swap them.  Of course that's not what I did

Also, Spookshow (http://spookshow.net/loco/mp282.html)  describes the two little latches under that hold the cab in place. Once they are released (requires a little screwdriver or some such) the cab can be wiggled off to the rear - IFF you have taken off the tender shell first.   Putting it back on is a little tricky, as the latches hold the red and black wires into little grooves in the frame and you have to tuck the wires into place. [/never mind]

[SkipGear]

The speaker is just held in with double sided foam tape. It should just pull out. Just be careful of the wires.

[brokemoto]

One thing to note about popping the cab off of the MP USRA lights:  it is EXTREMELY DIFFICULT to get the cab to go back on properly.  In many cases, it sits funny; it just will not go back on properly.

[nickelplate759]

One thing to note about popping the cab off of the MP USRA lights:  it is EXTREMELY DIFFICULT to get the cab to go back on properly.  In many cases, it sits funny; it just will not go back on properly.

Yeah, well it often sits funny right from the factory.  It's certainly a pain to get it on right.

[nickelplate759]

Finally moving forward on tender replacement for the 4-6-2.  Recall that it's from the last MRC production run.
I ended up choosing a Bachmann USRA medium tender that is NOT DCC ready - 'cause I have a couple lying around.
It does have 8-wheel pickup, and there's room enough inside for a decoder AND KeepAlive (not doing sound).  Modifications are in progress to mate it to the 4-6-2 drawbar.

The MRC version is DCC-ready - it has 6 wires from the engine to the tender - the four in the drawbar are the DCC standard Red, Black, Orange, and Gray.  There are two more Black wires for the headlight NOT in the drawbar.   The headlight lights up regardless of polarity on those wires, but it's constant brightness, and not terribly bright.

Anyone know if the headlight is in fact an LED, and if it needs a resistor installed?  I'm not excited about pulling off the boiler just to find out.

[SkipGear]

On the old versions, it was an incandescent bulb soldered to a circuit board with two wipers that contacted the tops of the front drivers. Pretty hoaky setup and made it a bear to add lighting control with out disassembling the entire loco. If it is constant brightness I would guess it has been replaced with an LED shining up at a light pipe that goes through to the headlight. The old light bulb was most definitely not constant brightness.

 

[peteski]

On the old versions, it was an incandescent bulb soldered to a circuit board with two wipers that contacted the tops of the front drivers. Pretty hoaky setup and made it a bear to add lighting control with out disassembling the entire loco. If it is constant brightness I would guess it has been replaced with an LED shining up at a light pipe that goes through to the headlight. The old light bulb was most definitely not constant brightness.

If it is an LED, then I find this statement puzzling; "The headlight lights up regardless of polarity on those wires". Unless there are 2 LEDs in reverse parallel.

[SkipGear]

Would not be too hard to put for diodes in a bridge to make it direction independent. Either way, if it is just connected to Pos - Neg from the loco pickup a resistor would not be needed because those wires would be seeing full track voltage.

[nickelplate759]

Would not be too hard to put for diodes in a bridge to make it direction independent. Either way, if it is just connected to Pos - Neg from the loco pickup a resistor would not be needed because those wires would be seeing full track voltage.

This is what I think is in there.  May need to open it up to find out.

[spookshow]

The old Model Power pacifics had an incandescent bulb for the headlight mounted to the chassis (receiving its current from a couple of annoying driver wipers) -



The MRC pacifics have an LED board mounted up inside the boiler (receiving its current from the aforementioned duo of wires from the tender). My picture only shows the absence of a bulb 



I don't remember how I determined that the MRC's have an LED, but it's in my review so it must be true 

Actually, now that I think about it, it may have been MRC that said the headlight was an LED - which should be taken with a grain of salt. They said a lot of things about that locomotive that weren't entirely true.

-Mark

[peteski]

Would not be too hard to put for diodes in a bridge to make it direction independent. Either way, if it is just connected to Pos - Neg from the loco pickup a resistor would not be needed because those wires would be seeing full track voltage.

I agree, but when lights are factory-installed, they usually  make them directional.

The 2 reverse parallel LEDs method behind the headlight lens for non-directional lights is used in the Atlas American (4-4-0) loco.

[spookshow]

I agree, but when lights are factory-installed, they usually  make them directional.

None of the various versions of the Model Power / MRC 4-6-2 have ever had directional headlights.

-Mark