Two of my first O gauge locomotives were Marx-Tronic switchers. For the unacquainted (most of you, I imagine), these were the "train with a brain", part of an automated switching set. The locomotive was powered by a single D cell.
And therein lies the problem.
The old lead acid D cell batteries of yore were prone to leakage. As a result, you are hard pressed to find a Marx-Tronic locomotive without corrosion damage.
In the case of one of mine, the damage was substantial.
But before we go into the technical aspects of these locomotives, there is one thing that needs to be pointed out. In volume 2 of "Greenberg's Guide to Marx Trains", the author states that these are Davenports. That's not the case. While Davenport did make a similar locomotive, this locomotive is based on a Vulcan Iron Works design, near as I can tell that was originally made for the US Navy.
Not only that, Marx apparently based theirs on Lionel's. The Lionel unit on the left is a more recent iteration, but still uses the classic shell casting.
That's the Lionel unit on the left. We'll talk more about that shortly, but as you can see, Marx was really cutting it close. While there are differences, the similarities are extreme. I wonder if this is part of the reason why the Marx-Tronic was only available for a couple of years?
Back to the corroded unit.
Marx made two versions of this switcher, one where the hood slid off for battery access, the other where the entire shell had to be removed. I have both, but for this project, I chose the one piece shell.
Trying to repair the old chassis was proving to be quite difficult. Even removing the driving wheels was a disaster, as one broke. In the end, I decided that the best thing to do with the damaged unit was to build a new chassis and redesign the model to run on 12 VDC. A Tamiya 70103 Universal Gearbox was chosen for the project, swapping out the 3 VDC motor for a 12 VDC version (FK-103 for the curious). Wheels are Marx diesel wheels.
There was one problem, though - the axles for the Tamiya gearbox are metric, whereas the Marx wheels use Imperial "Standard" axles. Since the front axle was non-powered, this wasn't a problem. For the drive axle, I used thin aluminum shims cut from tubing and chose the hexagonal axle from the kit, trimming it to the same length as the Marx axle. A little Shoe Goo helps to keep the wheels in place.
Also, the little nubs on the Marx axle were filed down. While these are used to keep the wheels in place, the chassis was sufficient for this.
The chassis itself was made from heavy polystyrene sign plastic. The initial design put the locomotive too high, so the chassis was redesigned to fit into the locomotive.
What isn't visible here are the wooden braces inside the shell, and the T-nut at the front that holds the chassis in. The rear of the chassis is held in place by a tab.
There were lots of minor changes to the design, such as the pick-up shoe (which is now two piece). Also, it doesn't have a lot of traction, due to the lack of weight - this will be remedied with "Bullfrog Snot" or something similar. Also, 3 oz. of weight have been added over the drivers, which help a little.
For now, stalled on couplers, but at least it is underway.
As for the other Marx-Tronic Vulcan. It, too, had corrosion damage, but not nearly as severe. It was treated with Naval Jelly and a wire brush. The motor was replaced with a modern unit. Currently, it runs, albeit a little fast in my opinion.
So now my line has three Vulcan switchers at various stages of operational capacity.
May they live long and prosper.
No comments:
Post a Comment