HO Bachmann Spectrum 44 ton to HOe/HOn3 Oahu Railway GE 47 ton

Canopus

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In this thread I will be documenting the progress of a project to convert the bachmann model into a close-as-you-can-get representation of an Oahu Railway 47 ton diesel. The format of this thread will be designed so that those of you who wish to have a go at this project can follow the steps to make their own model. Since this locomotive is essentially a GE 44 ton switcher with a new chassis, it will simply be a matter of removing the pilot ends, chassis, and cab, then modifying the cab to sit slightly lower down. After that we will cover replacing the cab, as well as additional details like toolboxes, modified handrails, moving the stepladders to their appropriate location, scratchbuilding the truck frames, and sourcing and modifying the chassis in order to motorise the model.

I'm currently in the process of actually acquiring the donor model for the project, so I can't start yet, but to get us started off for now here's the set of drawings we'll be working from:
 

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jetrock

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Are you going to use the original Bachmann motor and frame? Or motors? Bachmann made two versions of the 44 tonner--the first with two integral power trucks, the second with a single motor in the middle with ball & socket transmission.

The body work seems pretty straightforward--the ends are pretty much stock, and the cab would simply need to be cut down. Is the narrow gauge version narrower in body than the original model?
 

Canopus

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jetrock said:
Are you going to use the original Bachmann motor and frame? Or motors? Bachmann made two versions of the 44 tonner--the first with two integral power trucks, the second with a single motor in the middle with ball & socket transmission.

The body work seems pretty straightforward--the ends are pretty much stock, and the cab would simply need to be cut down. Is the narrow gauge version narrower in body than the original model?
Hi jetrock, some good questions there. I'll try to answer your questions in the order you asked them, so that we don't get lost here. :D

First of all, no I'm not going to be using the original motor or frame. This will be removed immediately and kept behind as spares for a seperate On30 project. I will actually be advising once I start the project, that modellers who want to do this project for themselves acquire the model in BODY ONLY form as a spare from bachmann if they can, rather than buy the whole model and have no use for the chassis (that is unless of course they intend to use the chassis for an On30 project like I'll be doing). You CAN use the original motor, but this isn't as simple as using a donor motor from an N gauge chassis.

The narrow gauge version was the only version of the GE 47 ton available. As far as I know they were never regauged. But I don't think this is what you meant by your question. I'm assuming you want to know whether the original GE 44 ton is wider than the 47 ton version - the answer to that question is no, it wasn't narrower or wider or anything at all, it was the same width. The only thing that GE did was build a new chassis, and lower the cab - this is basically exactly what the modeller has to do. As with any standard gauge locomotive that has been converted to narrow gauge, it looks a bit odd being so much wider than the tracks, but such is the way these locomotives are in real life.

As a side note, my Bachmann 44 ton is ordered and will be on it's way soon. Coming all the way from Rockford Illinois apparantly. Will take about 4 to 10 days to get here, but as soon as it arrives I'll get started posting photos of the various stages of the project. I'm a bit miffed actually because I missed a pair of undecorated 44 tonners that went for dirt cheap, and I had to order one close to full price (although the American "full price" is admittedly much cheaper than the British "full price"). Hopefully I won't get smacked with a customs charge upon arrival - I got that the last time I ordered from the US, and was tempted to dispute the charge because they hadn't even opened the package!
 

jetrock

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Perhaps some advice for other modelers trying this would be to find some trolley modeler who buys up the 44 tonners for their power trucks.

Rockford? Heh. My dad went to college there.

Looking forward to seeing the conversion. Didn't Bob Hayden convert a similar 44 tonner to HOn30 for the Carrabasset & Dead River Railway?
 

Canopus

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jetrock said:
Perhaps some advice for other modelers trying this would be to find some trolley modeler who buys up the 44 tonners for their power trucks.

Rockford? Heh. My dad went to college there.

Looking forward to seeing the conversion. Didn't Bob Hayden convert a similar 44 tonner to HOn30 for the Carrabasset & Dead River Railway?
Yes, Bob Hayden did indeed make himself an ex-Oahu 47 ton locomotive from the Bachmann 44 tonner. If you watch his video you'll be able to spot it in several places. A nice model it is too.
 

Canopus

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Well, the loco has arrived and I've started work today, here's a photo of some of the things you'll possibly need. A donor chassis/motor and wheels with gears, the spectrum GE 44 ton, and the plans for the components of the 44 ton.

Fresh out of the box, as is the donor chassis. I prefer using new donor chassis as they tend to have less problems to sort out than donors that have sat around for years.
 

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Canopus

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Next is removing the cab. The cab is handily a seperate part, so it can be removed without sawing. The cab is attached to the rest of the shell by four lugs, and removing it is easier said than done. First, you remove all the detail parts that might be damaged by handling the shell. You need three hands, and steel pinchers for fingers to remove the cab, but it can be done by pinching two of the lugs in while lifting that side of the cab out, then jamming a flathead screwdriver into the gap to keep it open, allowing you to do the lugs on the other side and lift the cab free.

With the cab seperate, you'll note that there's a little guy sat in the drivers seat, and an empty seat on the other side. These should be removed, and if you intend to use the driver again, I suggest repainting it, because it's not very well done.
 

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Canopus

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On the cab there are small steps which need to be removed to allow the cab to be lowered into the frame (the cab itself is not cut down, but we'll get to that later).

Simply saw off the majority of the steps, then wittle the rest down with a craft knife until it's smooth. Don't attempt to round out the edges to match the rest of the body, leave it as it is until the shell is reassmbled.
 

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Canopus

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Now comes a bit of a scary bit... well, it seems scary just before you do it, but once you've done it you realise it's not that bad. You need to seperate the noses from the base of the cab, by cutting through the floor just behind the nose. I found the best way to do this was to line up the saw with the edges of the lug holes.

Once you've done that, clean up the edges, and remove the little rim on the end of the nose that was designed to get the nose to fit snugly inside the hole of the cab.
 

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Canopus

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Next thing to do, is to modify the exhaust stack covering so that it's shorter. The best way to do this is to first make a cut into the stack from the front at the same level as the top of the smaller inner two windows. Then you cut very carefully (minding not to marr the windowframes and scratch the surfaces with the blade of the saw) from the bottom up the back of the covering, until you reach the cut you made. Reaching this point, the unwanted piece should fall away. This stage rewards careful cutting. Clean up (carefully) the area and sand it, and remove the windoframe trim from the two inner windows.

Also, remove the windscreen wipers. Nice as they are, they not only get in the way, but are also unprototypical.
 

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Canopus

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Now that the stacks have been modified on both sides, the noses can be reunited with the cab. This stage requires glue, and there is no way to avoid using glue here unfortunately, but it's not that bad.

Simply glue the nose to the cab, adding a spot of glue under the stack, lining the top of the nose up with the tops of the inner windows. Do the same for both sides.
 

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Canopus

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Next step, remove all the details from the front. You'll need to do this for ease of handling and prototype reasons.

With the details removed, you can now cut up the pilot. Remove the foot plate thingies, to match the profile pictured. I accidentally de-attached the nose which hadn't finished gluing yet, hence the unattachment.

Once the you've got the pilots modified, get rid of the lift bars and stanchions, saving them in a plastic bag or something for later. In the spectrum box, you should find a little detail bag with a pair of alternative headlamps - fit these. You will probably find that while removing the default ones, they'll break, If this happens, just cut away what's left behind, and the push it inside the nose from outside. It should just push in and out, leaving an open hole for you to push in the correct headlamps to match the prototype.
 

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Canopus

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Next step, pick up the chassis and remove the truck sideframes, which will need to be used in the construction of the new chassis. The sideframes will need to be modified slightly to match the prototype, and as it is slightly difficult to describe what exactly to remove, refer to the photos.
 

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Canopus

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Okay that's all for tonight, so far we've covered building a complete bodyshell. Tomorrow we'll cover scratchbuilding the toolboxes or whatever they are onto the shell, and working on scratchbuilding the chassis. I'll talk about different ways to approach motorisation, and if there's time tomorrow we'll also go into modifying the detail parts to match the prototype.
 

Canopus

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lv4142003 said:
Did you replace the wheels with larger ones? lv4142003
I believe he said that he did not, since it was not noticeable.

I'm inclined to disagree that it isn't noticeable, but would rather say it doesn't make a huge impact on the appearance of the model. Since the model is mostly accurate, and since the wheels only make up a very small part of the overall model, I'd say it's not an issue unless you absolutely insist on prototypical details.

What I do question is his statement that the gears were 1mm in diameter! I'd accept maybe 3mm in diameter, I think that's reasonable. But a 1mm diameter gear would require an axle of approximately 0.5mm or smaller.

It is possible to purchase and fit replacement wheels of a larger diameter, but I'd only be repeating what's already been said by saying that sometimes it isn't practical.

Of course, scratchbuilding a chassis eliminates any element of compromise, but that takes a lot more skill, effort, and time (considering you have to track down and purchase all the corresponding parts).
 

lv4142003

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Canopus, did you finish the 47 tonners ? I haven't been here for a while and wondered if I missed the finish. lv4142003