The N scale Truck mounted critter thread- general ideas various prototypes

[dcutting]

I would love to see a TP56 made.

A Kato Mid Production SD40-2 truck would be a great starting point. Just needs a body and a motor... The motor may be the hardest thing to source...

Damn shame they are sold out currently...

I have some CAD files started for one using a NWSL motor and one of those trucks. Same problem, nobody wants to destroy an SD40-2 for a critter or two. I have thought about some other options and may return to this in the future.

David

[peteski]

I have some CAD files started for one using a NWSL motor and one of those trucks. Same problem, nobody wants to destroy an SD40-2 for a critter or two. I have thought about some other options and may return to this in the future.

David

Those trucks are usually available as a spare part (for about $15 per truck). But at this time I believe they are out of stock at Kato.

[Ed Kapuscinski]

There's an article about doing the Conrail "Bug" in a past Conrail Quarterly (but it was in HO).

[u18b]

I'm planning on sacrificing an SD40-2.

But it will be July before I can move forward.

I don't want to dismantle my FLEA since it runs so well.

So a couple of days ago, I ordered two more B driving chassis from Japan.  Usually takes about a month to arrive.
I'm in a busy spot with work, so July will work out good.

Hey Pete, if you have CAD drawings started, that would save me trouble making my own Corel Draw drawings.

[u18b]

I've already been collecting as many photos as I can find for research/modelling purposes.

Here is my album so far.

https://goo.gl/photos/WJgRsQCCg2PmeBS48

[u18b]

In that collection, there are three helpful pics to get started.

First some company plans.
Unfortunately, the plans say that they are not scale plans, but rather concept drawings for conversation.---- and they are right.



So what I did was note that the plans say 27' 10" from pilot to pilot.

So I imported that into CorelDraw and scaled it to exactly N scale.

I then imported this almost perfect side on shot.



And when I did that, you could tell the drawing was not a scale drawing.  It is underscale.

So I was planning on tracing over that photo to get started.

These dimensions are also helpful.



I was thinking what a great etched brass kit this would be.

[u18b]

Oh.
And I stumbled upon a wonderful hard to find roof shot.

This shot shows:

--There is a grill for exhaust for the CAT engine.

--the hood roof is actually peaked.  Impossible to tell from the side.

[randgust]

That unit is surprisingly visible and accessible at Hollidaysburg, PA - where it is the shop switcher for Curry Rail Services.   That's the same location where the Everett RR 2-6-0 #11 operates out of.   The overhead shot was probably taken off of the Rt. 36 overpass bridge.  Curry is in the old PRR/Conrail Samuel Rea car shop there and this is the shop switcher.

The Kato truck is pretty easy to do and will have superior adhesion and pickup for it's size.   The trick is getting 'non-rocket' performance out of it given the size of the motor.    When I did my 25-tonner, I mounted the Kato motor vertically in the cab driving the rear axle spur.  Everything fit.  Note the alignment of the cab with the rear axle and you can see that you 'might' be able to do the same thing here and get in a reasonable-size motor vertical in the cab, engaging the rear spur, and let the truck gears carry forward to the other two axles.

I don't 'think' there's room in there for a gearhead, but there might be.   Ideally, if you can get about a 5:1 or 4:1 reduction the speed range off a pager motor translates to much better speed and torque.  The Gizmoszone GH34VB series has several plastic gearheads that screw right to the front of the 12v Kato motor, but the basic flaw is that it's a poorly-supported plastic output shaft that works a universal just fine but couldn't support the side-thrust of a worm without a bottom or end bearing.   Most of your low-end plastic gearheads have this problem.

In a perfect world you'd find an SD40/45 truck where the truck gear drive was on the END, rather than the center, to allow more room for a motor and full gearhead.   Didn't somebody do that once?   Remember how Roco did the E-unit truck with the pivot on the truck center and the full gear tower on the truck end?   http://www.spookshow.net/loco/atlase7.html   That would be the way to do it and would easily adapt to a gearhead-size drive.   But if there was a six-axle SD40/45 truck built that way I can't find it.  Somebody please prove me wrong.

I also agree that etched brass would be the way to go here, would be perfect for accuracy and weight.   I'd probably go for it if I could find the right power truck - it really needs to have the worm gear tower be part of the actual truck and on the end.   If you could still buy Roco trucks it would be worth it to file off the sideframe and replace it.   Doable as a one-off but I'm always more interested in something feasible as a kit with available parts.

EDIT:  Holy crap!  I just found a new set of those E7 trucks on Ebay for $25 OEM original leftovers!    OK, pulled the trigger, I'm in at least for a one-off.    I can get a gearhead motor in it aligned horizontal, I'm good.    He's got one more set left, but if you miss that one, PM me and i'll split the first set with you Ron.   I'll just file off the E7 sideframes - I think I have an old SD45 set left somewhere.

[u18b]

Randy,

The Kato mid SD40-2 truck has the worm built into it.
It is the way to go.

I have also seen that the Kato B unit driving chassis motor is the absolutely perfect size- almost like they were made for each other.

As for speed- with this compact combination of motor and truck, there is plenty of room for weight and a decoder.

I'm really looking forward to building a test model and hope that maybe some of us can pool our resources and develop a kit for this.

I know some don't have soldering skills and would rather have a styrene shell, but I'd rather have an etched brass kit that I could assemble.

Of course, once you make one.... you could thicken the walls and then make castings.

Or maybe some good Shapeways person will make a shell.

[u18b]

Hey if you want to freelance.....

The SD70ACe trucks are designed the same.
And Kato has those in stock.

[randgust]

This truck?

http://www.katousa.com/images/929343.jpg

Still puts the gear tower above the center axle, and I really want a gearhead and room for it.   That little guy is a slow-speed mule by definition.   My experience with the Kato pager motor on the 11-105 is 'OK' but put a 5.14:1 gearhead on it and it is absolutely phenomenal.   I've repowered everything I have that has room for that combination.

Now, these motors at the page top are the EXACT SAME CASE as the Kato 11-105 critter motor.   I buy them just for the gearhead and toss the 3.5v motor.
http://www.gizmoszone.com/shopping/agora.cgi?product=Gearmotor;ppinc=1g

For that price of a motor and a gearhead I simply buy extras just in case one fails, but I have yet to have a gearhead fail.

Even with the best throttles I've got controlling those pager motors at slow speed without a gearhead is a challenge, even when 12v instead of 3.5.   With a gearhead the torque and switching speed is pretty darn near perfect.

If you're doing drawings I'll trade a truck for those rather than have to figure that out myself....

[Lemosteam]

I could model that shell in an evening, but the trick is how would that shell attach to the truck, I don't have one.

[peteski]

In a perfect world you'd find an SD40/45 truck where the truck gear drive was on the END, rather than the center, to allow more room for a motor and full gearhead.   Didn't somebody do that once?   Remember how Roco did the E-unit truck with the pivot on the truck center and the full gear tower on the truck end?   http://www.spookshow.net/loco/atlase7.html   That would be the way to do it and would easily adapt to a gearhead-size drive.   But if there was a six-axle SD40/45 truck built that way I can't find it.  Somebody please prove me wrong.

Bachmann Dash 8-40C/CW (first generation) has just such an arrangement. The worm is integral with the 6-wheel truck and at the front of the truck. See http://spookshow.net/loco/bachdash8.html  But it is a Bachmann design, high-friction truck with white (cracking-prone) gears and wheel-back wipers.

[u18b]

I'm suggesting that we move the TP56 discussion to it's own dedicated thread.

https://www.therailwire.net/forum/index.php?topic=42126.0

This current thread is fine for a general discussion of all the possibilities.

But there seems to be a LOT more interest in the TP56.

[up1950s]

To use the TP-56 theme in pre '60s an Alco RSD-4/5 truck or an EMD SD-7/9 could be used under an elongated Plymouth critter shell .