May Trolleyville Times

The Real Fun in Model Railroading!
- Making Existing Items Work! -

Some time ago, a group of model streetcar enthusiasts decided to develop and produce an HO scale 3D printed model of the 11-window Baltimore Semi-Convertible cars and they asked Custom Traxx to make a set of decals for the car. So they did the research using the Trolleyville Library and data provided by Dr Richard Allman of Villanova, PA and the East Penn Traction Club and the results was decal set CN-5001, printed by Highball Graphics.

As a reward for work, Custom Traxx was provided a slightly damaged 3D printed shell of the car. After repairing some broken window frames and "knee " beams, it was decided to try and use the Bowser traction drive on the car.

As I was mulling around the possibilities of motorizing this car including some older brass drives that I had stored for such an eventuality, I found that I had been lucky enough to acquire and store away some Bowser Brill floors which are no longer available and have not been available for about ten years.

Weight is always an issue with 3D printed bodies as they are so light in weight and in some cases very delicate. The BTC shell that we inherited weighed in at 1.2 ounces and .5 ounces of that weight were two added 1/4 ounce weights. The smaller but metal Bowser Brill shell weighs 3.7 ounces and the current Bowser drive was designed in the late 1990s considering that weight level.

I got out my old HO scale Bowser Brill Suburban the body of which had been painted and lettered as Philadelphia Rapid Transit #3121 in 1967 while on alert as a Missile Combat Crew member in a Missile Launch Control Facility in North Dakota. I had been dissatisfied with the old 6' 4" wheelbase trucks for years so when the 4'10" wheelbase Bowser drive came out in the New Orleans cars, in April 2013 I converted the car to the Bowser 125130 drive using one of the Bowser/AFFA dynamically balanced motor-flywheel combinations obtained from AFFA-assembled PCC cars with defective circuit boards.

I put the new on top of the old Bowser Brill and found immediately that the main bodies of both cars were almost identical in dimensions. Only the platforms were of different sizes.

As I was mulling around the possibilities of motorizing this car including using some older brass drives that I had stored for such an eventuality, I found that I had been lucky enough to acquire and store away some Bowser Brill floors which are no longer available and have not been available for about ten years. I looked at one of them and thought that it might be simple to use this floor with a Bowser traction mechanism in the Baltimore Car.

This rest of this article is about converting the Bowser Brill metal floor, former Bowser part #1285, to use in this car. I realize that the floor is no longer available from Bowser but this was so enjoyable I had to write about it here.

Bowser Brill Suburban Floor part #1285 - not currently produced!

Because I had already done this almost seven years previously with the Bowser Brill and even used the same Bowser/AFFA dynamically balanced motor/flywheel combination, I thought this could be somewhat simple. So when we first laid the Bowser floor on the bottom of the BTC shell, it appeared that once we cut off the platforms of either the BTC shell or the Bowser floor, it would almost be a "drop-in".......well it was not.

The first of many issues that erupted was the width of the Bowser floor versus the interior width of the BTC shell. This made it obvious that a "drop-in" was not possible, we started taking very accurate measurements:

Bowser Brill Floor Exterior Width - 27.24 mm BTC Shell Interior Width - 25.60 mm

Bowser Brill Main Body Length - 104.96 mm BTC Shell Main Body Width - 105.2 mm

Bowser Brill Body Shell Total Length - 146.1 mm BTC Shell Body Shell Total Length - 153.0 mm

It quickly became obvious that we were going to have to remove 1.64 mm from the overall width of the floor (or 0.82 mm from each side) just to get the Brill floor to fit inside the BTC shell. In a stroke of luck, we noted that the Bowser floor has two length wise supporting gussets that are each 1.66 mm wide so we would be able to remove 0.82mm from each gusset and leave a 0.84 mm gusset on each side and that is exactly what we did. We visited fellow SCTC club member John McWhirter, shown at right,who employed his belt sander and calipers to slowly remove the excess width from the sides and not remove any more than we wanted.

The next photos show areas that we sanded or filed to get the previously painted black floor to fit the BTC shell:

Note: Extreme caution must be used when filing or sanding the edges around the opening for the power truck or the kidney shaped opening for the trailing truck pickups. Too aggressive and / or filing breaks the floor at those points and the floor becomes worthless for this endeavor..

Bowser modified #1285 Top View.

Bowser modified #1285 Left Side View.

Bowser modified #1285 Bottom View.

Bowser modified #1285 Right Side View.

There are more issues with the power truck and the trailing truck that must be mentioned.

For the power truck:

If starting with a stock Bowser Brill Suburban or one that has been upgraded with the A-Line #20040 Flywheel kit, there will be adjustments required with the drive line since the distances from the motor to the power truck are changed.

The 4'10" bolster, Bowser part #1388, may have to have the extreme ends shaved a little to fit between the gussets on the Bowser Brill floor, Bowser part 1285. The #1388 is slightly wider than the #1264, shown below left, which is the bolster used in all other Bowser RTR Trolleys.

Remember that the power pickup, Bowser part 1377, shown above right, on the power truck is not mounted in the same manner as on the Bowser PCC trolleys. It is mounted in reverse with mounted with the wire connection tab adjacent to the body of the power truck in line with the first axle.

For the trailing truck:

The part #1377 can not be used as manufactured on the trailing truck due to the fact that the kidney shaped hole in the Bowser floor, designed for the trucks and a power pickup with a 6'4" wheelbase, does not line up with the 4'10" wheel base truck power pick up, part #1377. You must cut off the tab to which wires are attached just to get the truck on the floor. There are a few ways to fix this but we did not want to remove any more of the floor since we know we have a weight problem to deal with.

Our method was to solder a 2" piece of #26 nickel silver trolley wire to the rear edge of each parts #1377 as shown in the next photo. They fit right through that kidney shaped hole in the Bowser Brill Floor. These wires will be given a piece of shrink tubing where they would strike the floor and they will then be attached to the motor or decoder. It is important to solder these wires to the edge of the #1377 (not the sides) to avoid interference with the wheels. We will see how this works in service.

The next decision was the platform floors. Do we cut the platform from the floor or remove platform material from the shell? Our shell already had three 1/4 ounce weights cemented to the roof and both the top and bottom of the front platform plus a styrene support for a floor in work by the original shell owner that was attached with ACC. We were able to remove the weight from the inside of the roof but neither the other two weights nor the support without possibly damaging the shell beyond repair. 3D printed shells tend to be somewhat fragile. So we opted to cut the floor to fit the shell and began to fit the floor inside the shell when the third problem arose.

The body had six 'stops' molded into the side to support a floor but they were in the wrong location to support the thicker Bowser floor so after some thought they were removed and two 85mm lengths of Evergreen Strip Styrene #157, 060" x .156", were affixed to the insides of the shell 3.78 mm from the bottom of the shell as new 'stops' for the Bowser floor.

So we were now ready to test fit the floor into the BTC shell when we discovered that those "knee beams" which support the front platform and are visible under the sides next to the steps are very fragile. We broke two of them and had to rebuild them with styrene strips. These "knee beams" had to be cleared by the floor since they sloped toward the center of the shell. So the floor had to have additional tapering at both ends to fit under those "knee beams" and due to the large hole in the floor for the 76" wheelbase mechanism, this tapering eliminated most of any platform on the both ends. All such taping had been completed before the four photos earlier in this presentation were taken.

Our floor is inserted into the shell using the the power truck end, carefully avoiding those "knee beams" and then pops in or slides back to the proper position under the rear end "knee beams" with no screws necessary. It will be held in place by a small dab of Walthers Goo as the present tight fit gets loosened during service. One final adjustment had to be made to get the floor even. We added two fiber washers under the bolster on each side of the mount to lower the power truck relative to the floor.

The final photos are of the Bowser 125130 mechanism mounted on our modified Bowser 1285 floor, and the body shell mounted on the floor and mechanism. After the photo was taken, we removed a fiber spacer between the trailing truck and floor and added two fiber spacers between the power truck bolster and the floor to keep the drive shaft as perfectly horizontal as possible.

The car at right is a stock Bowser Brill Suburban painted in 1967 as Philadelphia Rapid Transit Co #3121 in a North Dakota Missile Launch Control Facility. The car at left is our Baltimore Semi-convertible.

Note: In trying to make a complex subject simple, we may have missed a detail or two. If any reader has questions, please write George Huckaby at traxx@earthlink.net, call at 310-990-5422, or fax at 310-475-5597!

This car shell is currently available from Tram Works. (https://model-trams.com).

In Part Two will discuss finishing the car.