Re: Weekend Update 6/28/26

[wm3798]

I had a great time running with the Modutrak crew at the NSE convention in Milwaukee.
I finished this the night before leaving for the setup.
(Attachment Link)
(Attachment Link)
It’s an ai generated 3d print that’s been modified by milling the underside to accommodate the 7x16mm dual shaft coreless motor driving both axles with Z scale wheels and geared axle tubes from a worm at both ends.
It has an ESU Lokpilot decoder and a TCS KA-N1 keepalive. I ran short of time but it may get lights and an operating beacon.
The mechanism is basically the motor glued between two pieces of brass angle. The printed Z scale geared axle tubes hold the gauge and the half axles pass through holes in the vertical web of the angle providing track pickup.
(Attachment Link)
Much of the top web was cut away to allow the printed rubber tires to set down on both sides of the motor.
All of the motor and gearing is below the sill height and the rear hood is a solid block of lead. There is also a lead weight under the cab roof. The decoder and KA reside in the cab.
The video is of it running is on the mainline at about twice the speed it should be. It will slow down to a steady crawl though and pull 3 to 5 cars depending on what type.

/>

Amazing work, Jim.  But I have a question.  Aren't most of these critters propelled by the rubber tires providing traction on the railhead, with the steel wheels only serving to guide the vehicle on the rails?  As such, do you think there's a way to use "loose" axles to allow the big tire wheels to roll?  I'm open to being wrong, but I'm pretty sure that's how they work typically.

Lee

[Jim Starbuck]

Amazing work, Jim.  But I have a question.  Aren't most of these critters propelled by the rubber tires providing traction on the railhead, with the steel wheels only serving to guide the vehicle on the rails?  As such, do you think there's a way to use "loose" axles to allow the big tire wheels to roll?  I'm open to being wrong, but I'm pretty sure that's how they work typically.

Lee

Thanks Lee

I’ve seen a few different versions from various manufacturers. We have a Shuttlewagon where I work and it operates just like you said. There are actually grooves in the tires that sit on the rails with small rail wheels keeping everything lined up. Some have a knurled (for lack of a better term) hub in the rail wheel that the rubber tire presses against to drive it like the smaller Swingmasters have. I have also seen where there are hydraulic or maybe planetary hubs driving the rail wheels with the rubber tires fully retracted and only used to move off the rails. The Trackmobile Hercules looks to have different drives on each axle. Compromises were made to get this bug to run and the small diameter Z scale wheels actually help in the slow speed performance.

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I did explore overlaying printed rubber tires onto big rail wheels but to get the big wheels operating on such a small machine the motor would need to be above the axles in a turnback arrangement to accommodate the extremely short wheelbase and there isn’t any hood to hide the motor like a small end cab switcher.
This is a concept model in collaboration with a friend who wants to eventually develop a RTR or possibly kit version with commercially available parts.

[Jesse6669]

I planted some greenery on the East Norwood (more info here), and I made some chassis for the containers I designed. 

These started as a Thingiverse model of an N-scale 40' chassis that I re-scaled to Z and modified by lengthening to 48 and 53 feet, fixing a couple bits to make stronger for Z-scale, and added mudflaps; I'll post them up on Thingiverse once I'm 100% happy with the design. 





I also took a trip to Mendocino, CA and stopped at the old California Western yard/engine house and saw the new 250th loco.  This is now the Mendocino Railway.  The RR used to serve a Georgia Pacific lumber mill (now razed), pulling loads to Willits and the SP:

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[towl1996]

Hallelujah, the pics aren't upside down, lol. Showcase Miniature's firetrucks.

[Frank Amato]

Worked on some weathering this weekend; this is an iM 1937 boxcar lettered with K4 Decals (and reweigh patch from a Microscale sheet).  Grey/silver patches on the roof, an overall burnt umber oil wash with some darker acrylics around the lower door and track.  N-possibles and trucks are ready to go as soon as the wash is dry!

[John]

Nice job .. not too much, just right IMHO

[davefoxx]

I recommissioned and back-dated Georgia RR GP40 751 (shown here with Seaboard Coast Line SD35 1910) by replacing stolen parts and removing patched “SBD” reporting marks, to allow me to run this Geep improve the April 1971 era on my layout.



More on The Carolina Sandhills Lines thread in the Layout Engineering forum.

DFF

[mu26aeh]

I had a great time running with the Modutrak crew at the NSE convention in Milwaukee.
I finished this the night before leaving for the setup.
(Attachment Link)
(Attachment Link)
It’s an ai generated 3d print that’s been modified by milling the underside to accommodate the 7x16mm dual shaft coreless motor driving both axles with Z scale wheels and geared axle tubes from a worm at both ends.
It has an ESU Lokpilot decoder and a TCS KA-N1 keepalive. I ran short of time but it may get lights and an operating beacon.
The mechanism is basically the motor glued between two pieces of brass angle. The printed Z scale geared axle tubes hold the gauge and the half axles pass through holes in the vertical web of the angle providing track pickup.
(Attachment Link)
Much of the top web was cut away to allow the printed rubber tires to set down on both sides of the motor.
All of the motor and gearing is below the sill height and the rear hood is a solid block of lead. There is also a lead weight under the cab roof. The decoder and KA reside in the cab.
The video is of it running is on the mainline at about twice the speed it should be. It will slow down to a steady crawl though and pull 3 to 5 cars depending on what type.

/>

Someone is working on trackmobiles in a Facebook group.  Hoping they come to fruition as I need one for my cement facility.  This kind of engineering is way above my paygrade, electronics etc are not my strong suit.  Excellent work !

[milw156]

Amazing work, Jim.  But I have a question.  Aren't most of these critters propelled by the rubber tires providing traction on the railhead, with the steel wheels only serving to guide the vehicle on the rails?  As such, do you think there's a way to use "loose" axles to allow the big tire wheels to roll?  I'm open to being wrong, but I'm pretty sure that's how they work typically.

Lee

I stumbled across this last nite from this Youtube video, small world, good timing!

/>

[packers#1]

When I was a customer quality engineer at my work Trackmobile was one of my customers, but sadly I never was able to create an excuse er, reason, to go visit them. I always figured our hydraulics were used to deploy the railroad wheels, but we absolutely have the parts and systems which could be used to drive the railroad wheels as well.

[randgust]

I got my trackmobile to work quite well years ago, but the bugaboo was always pickup when limited to 4 contact points when one wheel always followed the 'three legged stool' problem.    I ended up adding a pickup car made off a Kato 11-105 pickup truck and made into an attached scale test car.   Then it was flawless and practical to use as a switcher.   



Link:  http://www.randgust.com/TMB20.jpg

That 11-103 chassis is no longer made by Kato, the 'secret' to that attempt was ditching the 42" wheels and putting in Kato 27" wheels.


So it isn't just the drive, it's engineering the pickup and equalization to get a really good one to keep all four feet on the floor.

And every real trackmobile I've worked with uses the rubber tires to drive around on surfaces and the steel railroad wheels for propulsion on tracks.   Also remember the 'secret sauce' of any trackmobile is the ability to literally jack up the coupled car it is attached to to transfer weight to the trackmobile for tractive effort.   That's why you'll see the 'hydraulic claw' and vertical cylinder around the end couplers.

[Jim Starbuck]

The rail wheels on my Trackmobile are Z scale which scale to 24” in N. It is electrically independent but this is in large part to having a keepalive in the cab. The rail axle spacing is 22mm so it’s stretched out as far as possible so it does span various parts of switches and such.
The biggest problem is the ends of the worms interfere with any kind of coupler box so the end plate is just a piece of styrene with a slot and the shank and knuckle of an N-Possible glued making it a dummy so I can’t back up and simply couple to a car.
This is still very much under development but I was glad to have it at least running at the convention.

[keeper]

I built a tower for Z T-Trak layout. It is another very nice kit from Archistories.

[randgust]

The rail wheels on my Trackmobile are Z scale which scale to 24” in N. It is electrically independent but this is in large part to having a keepalive in the cab. The rail axle spacing is 22mm so it’s stretched out as far as possible so it does span various parts of switches and such.
The biggest problem is the ends of the worms interfere with any kind of coupler box so the end plate is just a piece of styrene with a slot and the shank and knuckle of an N-Possible glued making it a dummy so I can’t back up and simply couple to a car.
This is still very much under development but I was glad to have it at least running at the convention.

Definitely a case for DCC when the solution for spotty contact is a keep-alive.   I've been using the Iowa Scale Engineering ones (Run-N-Smooth PowerKeeper) and have been very impressed.   Didn't exist when I built mine, and it's DC.

If it makes you feel any better my couplers are glued-on heads as well.  Adding that scale test car gave me an operating magnetic knuckle on the end for actual switching.

It's kind of a BS excuse, but if your TE depends on jacked up end weight, and you "found" a retired scale test car, and you have a really sharp curve that causes derailments if you jack a car normally, well, that's the story I concocted.

[Jim Starbuck]

I have a flatcar behind mine because it’s a conversion car with an N-possible on the front and an MT on the back since I only have two cars converted to N-Possibles right now.
That will get remedied since I bought couplers from Andrew at the convention.