PRR A5 in N Scale

[mmagliaro]

Beware the small Sagamis.   Sagami made great motors for their time, but the smallest, the 10mm x 13mm is not
such a great motor and that's probably the one you are looking at.   I believe that I pulled one of those apart at one time
and found that it is indeed only a 3 pole, unlike the 12mm Sagamis, which are 5, and they are head and shoulders better
than the 10mm ones.    The motor and running qualities of that Atlas engine are not bad.  I have one with all-wheel tender pickup and it runs
pretty darn good for such a high gear ratio.  I don't think a different motor would help unless you change the gears.

[VonRyan]

I was mostly thinking for DCC health since the engine will get a TCS Z2 in the tender.
Of course, I intend to retain the pickup from the drivers so power will have to get re-routed, which shouldn't be too hard to do with the lower chassis being plastic.

That being said, if you think that the original motor will withstand DCC, then that should be sufficient.
I was just thinking a new motor would allow it to run better with a decoder.

As soon as the B6 shell arrives, and as long as the temps don't drop too low, I can hopefully get the original Atlas shell on my friend's milling machine to begin making room for the B6 pieces.

[Ed Kapuscinski]

And don't forget, it's an engine that really needs slow speed performance. Running at all is one thing, but if you can't gently nose boxcars into buildings with it, what's the point?

[mmagliaro]

And don't forget, it's an engine that really needs slow speed performance. Running at all is one thing, but if you can't gently nose boxcars into buildings with it, what's the point?

... I agree, which is why a page ago, I suggested the 8mm + a gearhead.   You are going to want that gear reduction.
The Atlas engines were all geared at 15:1, which is really fast.    It should be geared at more like 50:1, at least.
You'll still be able to run it at 50 mph, which is probably faster than an A5 ever moved in its life and would still be
a perfectly acceptable mainline speed.

If you aren't going to gear it down, may as well leave the stock motor in there.   I hadn't heard of DCC PWM killing these motors.  I don't see why it would.

[mmagliaro]

Upon further review, Cody may have a point.

I dragged out my old 0-4-0, ground down the flanges so I could run it on my layout (I have not run it since I had ME code 55),
and then ran it for a while, cleaned it, and got it running smoothly again.  It has sat in a box for at least 5 years.

Upon testing, it really can't do any better than about 10-12 mph, and it doesn't really smooth out until you get up to about
15mph.  This is all with DC with some gentle pulses in it, and on that power, a good engine mechanism can crawl at speeds
under 1 mph.  For switching, 10 mph is kind-a fast.

Even though the gearing is fast, I do think that Cody is right about a motor after all.  A better quality, more powerful motor
would probably be able to move this thing much slower than the stock motor.   I'll pull the motor and compare to my stash
of motors, and see what looks like it might fit without too much trouble.   If your plan is to machine down the Atlas boiler
and plunk another one over it, then anything that can fit in there as-is ought to work out.

By the way, the gearing is "bad" in this (or any other) Rivarossi engine.  They were  too high a ratio, but
they were pretty darn well-made brass gears.

[VonRyan]

Max, you're work itself is an inspiration for me to push this project forward.
I very much appreciate your help.

I'm not 100% certain as to how much room I'll have if I allow the B6 Belpaire to remain hollow. It might allow for something of a longer motor to fit in there.

[mmagliaro]

Ugh!  I cannot edit! 
I meant, in my previous post, that the gearing in this engine is NOT BAD.   
And Cody, thanks for the words of praise, but none,... zero... are necessary.

And I am interested in this project because that engine is so small.  This will present some difficult and interesting
engineering problems to be solved.

[chicken45]

I'm calling it. It's going to happen.
He will come back.

[VonRyan]

Ugh!  I cannot edit! 
I meant, in my previous post, that the gearing in this engine is NOT BAD.   
And Cody, thanks for the words of praise, but none,... zero... are necessary.

And I am interested in this project because that engine is so small.  This will present some difficult and interesting
engineering problems to be solved.

Well, the B6 shell arrived today (Excellently packed I might add!) and it appears that with minimal milling of the Atlas shell, the B6 pieces will be able to fit right overtop. If this is done very diligently, it will certainly add a good bit of weight to it, which is a major benefit.

Tomorrow I'm going to be picking up some phosphor-bronze wire for the inevitable piping for this little beasty.


In the name of the Slope, the Curve, and the 4-Track Main... Amen.

[eric220]

I have a confession... It was packed in my car in the post office parking lot. I'm glad it made it in one piece.

[VonRyan]

I have a confession... It was packed in my car in the post office parking lot. I'm glad it made it in one piece.

The fact that your car carries foam peanuts in it for the occasional emergency shipment is both outstanding and concerning... 

The shell has a good home and a very certain fate.

[VonRyan]

Picked up some .008" phosphor-bronze wire today for piping and such (oh, and 4 other sizes that I forget).
Tonight starts the removing of the B6 cab and the chopping of the rest of the shell.

Hopefully the milling of the Atlas shell can begin tomorrow.

-Cody F.

[VonRyan]

I have a few progress photos to share with those of you following along...




^ Rough removal of the Atlas cab. This means that I have plenty of breathing-room for milling.



^ These two photos show the motor refitted onto the chassis. It turns out that the motor only needs two screws to be securely held to the chassis. This is good news as it does mean that the original motor and drive-train are able to be retained, unaffected.


This is all the progress for now. I may do some removal of parts of the front cab wall as time allows, as well as the stack and domes, just to same myself some milling time.

[VonRyan]

While sitting in the library during a 2hr gap between classes, I pulled out Pennsy Power I (which I brought along for just such an occasion) and studied the few images of A class engines.

In regards to my kitbash and how faithfully it will portray the prototype, there will certainly be a lot left to be desired. My goal is simply to make a reasonable facsimile of an A5 with a level of fine detail that is an underlying expectation here on the Railwire.
And although there will be some shortcomings, as long as the end result has enough of the look of the A5, and enough fine detail, then I shall not have failed. Of course in the future I may decide to make a more faithful kitbash/scratchbuild, this little warrior will stand to fill a void that shall never see manufacture attention, at least as long as I live.

[superturbine]

Sounds good to me!  I'll be watching.