Question regarding Athearn/MDC/Roundhouse locos

[brokemoto]

The Athearn mogul and consolidated tenders are the same.

The MDCs are different.  The consolidated has the wires soldered to the trucks.  In fact, many have issued the warning that you should not unscrew the tender trucks on the MDC consolidated under any condition.  When MDC issued the mogul, it went with the brass strips on the tender floor, similar to what B-mann does on the SPECTRUM and what Kato did with the USRA heavy 2-8-2.  When Athearn bought out MDC, it went with the construction methods on the mogul tender for both locomotives.

The spaces on those 1880s locomotives are tight, so you would think that the wires would have come unsoldered on the 2-8-0 over the years, but it has not happened.  I have several of the 2-8-0 s, including one that often does duty as a station switcher.  None of the wires have come unsoldered.  In fact, for a while the one that often works as a station switcher now was then frequently running on UNITRAM trackage.

[Dave V]

Hey, also...I was working on locomotives tonight and noted that the MDC/Roundhouse 2-8-0 tender is actually a bit shorter in length than the Athearn's as well.

[Lemosteam]

Hi Dave, not seeing this between my Roundhouse and Athearn units although I do see differences in the tender shell.

Also my Roundhouse does not have the tender hatch. This project is looking to be Athearn only at this point unless I can prove the Roundhouse tender chassis to be totally identical.













Here is a pic of the progress.

[brokemoto]

A word of caution when handling the locomotives.  Be very careful not to let the palm of your hand or a finger put pressure on the whistle.  This detail is very delicate and breaks easily. I have had to replace more than one.

[Chris333]

So John does the new motor mount allow for a shorter tender body?

[Lemosteam]

So John does the new motor mount allow for a shorter tender body?

@Chris333 , Yes.  The motor position allows for a 2mm total drop but it might be more with respect to the side view.  I will post some images in CAD later. if it does not look k good enough I can drop the top a little more by designing a new casting and print that in brass.  I am also designing a snap on tender shell that eliminates the screws and the snap in coal load.

My biggest worry is the u-joint drop may make the design unworkable and the drive shaft may not be able to work at the new angle.  I will definitely have to print some test parts first to test the design.

[Dave V]

A word of caution when handling the locomotives.  Be very careful not to let the palm of your hand or a finger put pressure on the whistle.  This detail is very delicate and breaks easily. I have had to replace more than one.

OMG, yes, LOL... 

[Lemosteam]

@Chris333 A work in progress side ide view comparison.  Current Athearn, my PRR H3 rendition.  I am definitely trying to allow the new shell to fit onto the old chassis with repowering, but a new motor cradle for the old chassis would have to be designed, one that lets the shell snap on from the sides. either that our the user could use a magnet or something.

I could lower the shell another millimeter, but that forces a completely new cast chassis (which I am designing anyway to test).  I don't think there will be many interested parties anyway.

Next up is the driveshaft and new motor coupling.

[StarCruiser]

The new shell definitely looks more proportional to most prototypes...

[Dave V]

Had I not already gone to pains to decal all my 2-8-0s for the Colorado Midland already, I'd be on board with a few!

[Chris333]

Wow that looks so much better!

[Lemosteam]

Current progress on the PRR-ization of the Ahearn model.  Trying to recreate the H3a class at the RRMPA on the Ahearn chassis:

[Chris333]

I don't know about that angle. Can you move the motor back further?

[Lemosteam]

@chriss333, to answer your question, yes I can move it back, but I intend to re-use the OEM driveshaft as it is Delrin and therefore slippery.  There is ample running clearance in between both cups and the shaft ends.  The angle is more a function of the height between the shaft centers and the length of the shaft spheres.

I have prints coming to test very soon.  Each cup allows the shaft end to move +/- 0.5mm.

Since I am designing a nwe cradle anyway. I could move the front end of the motor up and it might still fit within the tender shell.

I have been meaning to ask if you have ever used brass foil to wrap a shell.  K&S sell it. Was thinking that if I could put rivets on the model, wrap the brass over the side with .005 thick foil, the rivets could be embossed as you wrap by burnishing the metal with a stick. sounds messy though and prone to mistakes. I dunno.

[brokemoto]

Third Rail Pennsyised an MDC 2-8-0 many years past.  Photographs of it did appear here.  You might have to go looking through old topics as Third Rail departed several years past.