Rebuilding a Roundhouse Boxcab

[faraway]

Matt, I tried the original drive only ones on a test tracks. The sound and the sparks at the wheels are frightening and I put them never on my layout. The pilots and the shell are put aside and the heavy drive gets in the garbage immediately. I got some training making new baseplates to sit on the GE 44ton drive and hold the pilots and shell.

[sailormatlac]

As agreed between Reinhard and me a year ago, it's my turn to explain how I remotorized a Roundhouse boxcab. Unfortunately, the motorization is absolutely garbage. I tried a few time to figure out a way to salvage as much as I could from the old drive, but came to the conclusion it was useless. In fact, the way trucks are powered by a central mechanism makes the locomotive absolutely unable to manage sharp curves. Given Harlem Station sports prohibitive 13.5" radius curves in some parts, I had no choice but to think about an alternative.

However the year, a common trick had been to replace the original drive with a Bachmann GE 44-ton drive. The most popular method is to sit the boxcab shell onto the 44-ton frame. Most people keep the pilot of the GE switcher which is plain wrong and looks silly. Also, the GE truck sideframes are kept in place emphasizing the weird look of the loco. As you understand, I wanted to go another route. Powered trolley trucks were an option, but their prohibitive cost and performance wasn't very interesting. I like to experiment, but in this case, I prefered to keep things economical.

To be noted, the GE wheelbase, wheel diameter and wheel spacing are wrong too. Now, I had a challenge in front of me. How to make the GE 44-ton mechanism more acceptable and prototypical.

The first thing I did was building a styrene frame of similar size than the original metal frame to which I would attach the MDC "correct" pilots. It was a fast and easy build. Vertical styrene walls were built to prevent the frame to warp. They also provided a nice surface to add self-adhesive lead weights which is always a good way to improve performance. There's still a lot of space for a sound decoder and speaker.







The next step was the trucks. I decided to accept the wrong wheelbase as an inevitable trade off. However, the small GE 44-ton wheels had to go. Fortunately, the person who sold me the kit also provided an European Bachmann streetcar drive. The drive is exactly the same but the wheels are the correct diameter for a boxcab. It was just a matter of swapping the wheels and that big problem was now a thing of the past.



The last things I wanted to correct were the sideframes. While the Roundhouse sideframes are a little bit crude, they are still better than keeping GE trucks. To make them fit the new drive, I cut the metal pins behing the truck, grinded the bushing behind the journal boxes and slightly reduced the depth of the peg securing the sideframe to the truck.



With drill bits and cutoff wheels, I was able to notch the metal peg in such a way the sideframes could be mechanically attach to the truck's plastic pins. Be aware you will have to take time to adjust the sideframe height. Yes, the sideframe isn't a perfect match for the wheel, but it's almost imperceptible.



If I had to redo this, I think I would grind completely the sideframe metal peg and replace it with styrene. That way, it would be much easier to adjust the height.

Finally, my last modification was to remove about 0.75mm of material on the shell ends to make sur the carbody would sit correctly aligned with the pilot beam. The original Roundhouse design was a little bit weird because it didn't align. Now the shell sit properly!



I'll probably remove large part of the underframe diesel tank. Since I changed the wheel diameter, the trucks can't swivel freely. Also, only an air tank existed under Erie #20 and I'd like to follow the prototype as much as I can. It will also look more prototypical and eliminate the last visible remnant of the GE 44-ton.

All in all, I believing these slight modifications to the "traditional" way to repower the Roundhouse Boxcab with a GE 44-ton drive is closer to the prototype appearance while requiring no particular skills. It sure ain't perfect, but considering it the marginal cost and time involved, it truly makes a dramatic improvement. To be noted, correct AGEIR sideframes are available in 3D print which would be a nice addition to any model.

Another challenge will be to find a way to mechanically fix the shell on the underframe. I don't have yet an idea how I'll do it. Once done, the fun part starts by detailing and painting the locomotive. It shouldn't be too hard. In that regard, I don't plan to buy parts since I consider this a low budget conversion.

Matt

[doctorwayne]

....Another challenge will be to find a way to mechanically fix the shell on the underframe. I don't have yet an idea how I'll do it. Once done, the fun part starts by detailing and painting the locomotive. It shouldn't be too hard. In that regard, I don't plan to buy parts since I consider this a low budget conversion.

Matt

Nicely done, Matt.

One easy way to affix the shell on the frame is with screws. For your boxcab, I'd put a length of 1/8" or 1/4" square styrene strip material, upright, in each corner of the body shell. Keep it short enough so that it doesn't later interfere with adding 'glass' to the windows. The bottom end of the strips should just touch the floor of the underframe when installed, so if the frame fits into the shell, place the strips recessed accordingly.
Any size small flathead, 3/8" or 1/2" long screws will work - 2-56, 1-72, 0-80, or 00-90. Install the frame/floor into the bodyshell, then drill appropriately for the chosen screw size. Remove the floor, then tap the holes in the square corner posts. Use the proper bit to enlarge the holes in the floor to clearance size, then use a larger bit to countersink those holes, so that the flat screwheads will sit flush with the underside of the floor when installed. For a 2-56 screw, use a #18 bit, a #29 for a 1-72, #36 or 7/64" for a 0-80, and a #42 or 3/32" for a 00-90.

Wayne

[sailormatlac]

....Another challenge will be to find a way to mechanically fix the shell on the underframe. I don't have yet an idea how I'll do it. Once done, the fun part starts by detailing and painting the locomotive. It shouldn't be too hard. In that regard, I don't plan to buy parts since I consider this a low budget conversion.

Matt

Nicely done, Matt.

One easy way to affix the shell on the frame is with screws. For your boxcab, I'd put a length of 1/8" or 1/4" square styrene strip material, upright, in each corner of the body shell. Keep it short enough so that it doesn't later interfere with adding 'glass' to the windows. The bottom end of the strips should just touch the floor of the underframe when installed, so if the frame fits into the shell, place the strips recessed accordingly.
Any size small flathead, 3/8" or 1/2" long screws will work - 2-56, 1-72, 0-80, or 00-90. Install the frame/floor into the bodyshell, then drill appropriately for the chosen screw size. Remove the floor, then tap the holes in the square corner posts. Use the proper bit to enlarge the holes in the floor to clearance size, then use a larger bit to countersink those holes, so that the flat screwheads will sit flush with the underside of the floor when installed. For a 2-56 screw, use a #18 bit, a #29 for a 1-72, #36 or 7/64" for a 0-80, and a #42 or 3/32" for a 00-90.

Wayne

I'll follow your suggestion. It is indeed the only way to do it. There's just enough space required for the screws.

Matt

[sailormatlac]

Wayne, I did what you said and I'm pleased to report the shell is now firmly attached to the undeframe. And easy to remove for maintenance. Thank you.

Matt

[sailormatlac]

Over the last few days, I scratchbuilt the many details specific to Erie #20 boxcab. Over its life, this locomotive saw many changes to its cooling devices and exhausts. I mainly used scraps of styrene and sprues.

I decided to set the model in its later appearance when the paint scheme was simplified in the mid-50s. This locomotive, with boxcab #19, was scrapped in 1958. I'll only need to add details to the pilot and the model will be ready to be painted and decalled.







Matt

[cthart]

That's looking fantastic, Matt! While an up-to-date, detailed boxcab model is needed and would sell well IMHO, you've shown what can be done with some older models. Well done!

[Schraddel]

Yeah Matt!

The boxcab now looks like a model of an boxcab of up to date should look too.
I expect with great interest how you will make the headlights.

Cheers Lutz

[faraway]

That is great. The added details make the difference

[sailormatlac]

Thanks guys. Indeed, it would be nice to have something more up to date on the market.

Yeah Matt!

The boxcab now looks like a model of an boxcab of up to date should look too.
I expect with great interest how you will make the headlights.

Cheers Lutz

I'm planning to use a method I trid with some of my kitbashed steamers. A suitable LED will be tighly fitted on the headlight casting and the LED "legs" will be bent at a right angle and inserted into two small hole on top of the roof. Two feeders with connectors will be connected to the LED. This way, the headlight can be removed for maintenance or while painting the model. The shell can also be easily dismantled from the drive wasily.

Matt

[shortliner]

Oh, WOW! Doesn't that look different? Very, very nice job, Matt - and certainly shows what can be done to a simple plastic body-shell - very well done indeed

[sailormatlac]

Here's the locomotive with a coat of paint and decals. Decals are Microscale Erie Steam Locomotives (1930-1950). I couldn't source locally diesel decals and found out the steam ones were perfectly fine for the job. Why bother wasting time ordering a set when the available one suffer from no discrepancies except for the small letter "F" indicating the engine front end.



And if you ask why I painted locomotive #20 instead of #19 it's because I'm still sane enough to not attempt painting stripes over the locomotive ends! Well, I have another shell I could repurpose if I feel like it.

The headlight will be added when we rework the wiring and add a decoder.

Matt

[doctorwayne]

Great looking results, Matt.

Wayne

[cnrglen]

Great looking engine, Matt. I like your take on the spark arrestors

[modelsof1900]

Very good looking model. Excellent work and paint! Congratulation, Matt!