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Converting 3 rail diesels to 2 rail  

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(@andy-estep)
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Joined: 2 months ago
Posts: 4
30/08/2020 11:24 am  

As a relatively new convert to 2 rail O scale I can say that a huge area that would catch more new people is to have an easy to access posted article on how to change 3 rail engines to 2 rail engines would be a huge help. The number of manufacturers that offer new off the shelf ready to run 2 rail O scale engines as you know is very low and dropping. At the same time there are many 3 railers that would be more open to change over if there was a was a place to point them where to go to learn how to do this.

As a reformed 3 railer I have a large collection of engines that I want to run. My problem now is that I cannot because they are 3 rail. I don't want to sell and repurchase them in 2 rail. In most cases they are not offered in two rail.  The whole process seems like in the conversion to 2 rail I am wasting both time and money. If the 2 rail community wants to grow and bring in more members showing how to turn their engines into 2 rail engines is the most helpful way to bring them along. Other 2 railers have said, "There is a guy who does all of my conversions but he is about to stop doing this better hurry and get your things in". This is not reassuring to someone who is starting out that the guy who does this will be closing shop. It is like buying a powerboat from the one marina on the lake that is not going to be selling gas anymore.

What is the list of items that you need to perform this swap out. The easiest seems to be the swapping kit for MTH Protoscale 2/3 wheels but that program is ending with MTH next year. NWSL wheels and a puller seems the next step but how do you do this conversion? Can a link to a good basic article be posted because I have found that to be nearly impossible to find. 

My post just is asking about diesel conversion because it seems like an achievable goal for a beginner. Steam on the other hand seems a whole different ball game. Baby steps.

This topic was modified 2 months ago by Andy Estep

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(@martin)
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Joined: 3 months ago
Posts: 40
31/08/2020 9:29 pm  

NWSL used to sell conversion wheelsets. If they are no longer doing that, maybe a few phone calls letting them know that there really is a market for such items is needed.

MTH may simply be stranding folks; not much you can do about that.  When you state not offered in 2 rail - not at all or not in that paint/lettering scheme?  If the latter, consider selling off the 3 rail and buying a 2 rail engine with a plan of re-painting and lettering as an option

Converting stuff from scratch takes some tools and skills that many lack; Joe F. was doing this for the entire community pretty much single handed at bargain prices to the point where he did not have the time to do what he wanted to do for himself. That no one else stepped in to fill that void pretty much tells you that the costs involved are more than a person can charge realistically for their time vs. what folks are willing to pay. I used to pay him whatever he asked and was happy to do so.

O scale historically has been a DIY scale supported by a host of cottage/basement/garage vendors that come and go with the blink of an eye.

Either someone will come along that can and will do this sort of work at prices that folks are willing to pay or it won't happen.


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(@prr1950)
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Joined: 3 weeks ago
Posts: 2
03/10/2020 2:35 pm  

One of the major conversion issues is changing from 3-rail center pick-ups for power and command control to 2-rail power and command control delivery.  However, there are new products currently entering the market that may resolve those problems more easily.  These products are generically referenced as BPRC which stands for Battery Powered Remote Control.  With these products that rely on battery power and wireless remote control, you will no longer have to change wheelsets or worry about power shorts just because of the changeover to 2-rail.

Of course this technology is rather new and has its shortcomings (probably won't be good for long-running museum displays until technology is much improved), but it might present an easier way to convert to 2 rail O scale.

Chuck

This post was modified 3 weeks ago by PRR1950

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(@jwubbel)
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Joined: 3 months ago
Posts: 9
13/10/2020 12:45 pm  

Martin is right on the money with his comments. It has been a DYI scale and perhaps for us scratch builders that is the appeal and maybe the challenge. In reality it might be a great way to get started in O Scale 2 rail by doing a conversion or restoration on a piece. For the beginner, might I suggest a low cost way of doing something similar. There seems to be a good availability of Lionel diesel shells. I wanted a quick way to obtain a couple of GP-30 engines for my CGW. So I got busy making the patterns for the flooring and fuel tank with mount points. I prefer brass but the 3D printed patterns work okay too. The rest is adding detail and of course power unless all you want is a dummy engine. Once you build up from a shell, perhaps you can go onto doing the more challenging work of converting the 3 rail engine. Perhaps the problem is most of us 2 rail modelers have never been into 3 rail so the idea of conversions other than maybe an occasional freight car has never been a refined skill in the community. Maybe others can comment here on the topic.


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(@nyterm)
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Joined: 2 months ago
Posts: 45
13/10/2020 5:38 pm  

One of the greatest challenges in converting 3 rail locomotives to 2 rail operation, is the need to insulate wheels on the left side.

Conversion wheelsets did that easily for diesels. Now that they are no longer made, ways need to be found to insulate the wheels on the left side.

Why only the left side?  It stems from an early NMRA standard of recommended practice, to assure everything would work together on analog 12 volt DC power. 

This is because the right rail when positive should lead a locomotive forward.

When polarity is reversed and the right side is negative, the locomotive then runs in reverse.

For steam locomotive conversions, the project becomes much more involved.

However this blog is for diesels, so I will not go into any details about steam locomotive conversions.

Ed Bommer 


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(@martin)
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Joined: 3 months ago
Posts: 40
13/10/2020 10:28 pm  

"Perhaps the problem is most of us 2 rail modelers have never been into 3 rail so the idea of conversions other than maybe an occasional freight car has never been a refined skill in the community."

Simply popping off/in wheelsets is easy stuff.  I'm lacking in the skills of machining wheels to 2 rail standards and then including the insulation never having any real need combined with no place for the tools required for doing that sort of work. 


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(@andy-estep)
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Joined: 2 months ago
Posts: 4
14/10/2020 2:19 am  

Thank You all for the thoughtful responces.

As I said I am relatively new to the 2 rail side of O scale. I have existing O scale engines and rolling stock but my issue is  I would like to convert it to 2 rail if possible. I do have some access to machine tools. I am good with craft. I am willing to learn new skills if I need them. Since this lockdown started I have been scratch-building British 1860s era passenger cars in plastic but I do not know where to find out about how go about doing these conversions.

Is there a place that you can recommend for a primer on how to do this? Is every O scale 2-railer supposed to just grope around in the dark to reinvent the wheel every time? Is there no place to go to learn?

If there is not then maybe a basic primer for the new o scale convert may go a long way to recruiting new members to the scale. The largest section of the  O scale 3 rail manufacturers catalogs for the last 20 years or so is the "3 rail scale" area so there is a ton of it out there. I would imagine quite a lot more of that than 2 rail is around.

(For the record I have steam that I fully intend to convert but that can wait until I can get the basics down.)


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(@nyterm)
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Posts: 45
14/10/2020 6:17 pm  

Basically, the conversion of diesel locomotives and electrics without drive rods from 3 rail to 2 rail involves insulating the wheels on one side.

In 2 rail, the right side rail is positive and provides forward motion to a locomotive. The left side is negative in the power circuit of the tracks.

This is true for DCC set ups as well as the usual analog 12 volt DC power arrangement.

The diesels to be converted from 3 rail to 2 rail need to have the wheel sets removed from the trucks and their flanges turned down to NMRA standard for 2 rail if they are oversized.

Then, the left side wheels pressed off their axles.

These wheels have their axle holes re-bored to a slightly larger diameter, so an insulating sleeve can be inserted and the wheel pressed back onto the axle at the correct gauging.

It can be tricky to to, because the sleeve (usually some sort of rubber or plastic material) is compressed while doing so, in order to keep the wheel tight on the axle.

The way diesel power wheels are fitted to their transmissions can create difficulties in doing this. 

Often the wheels are close to the sides of the axle gear box or, the axle gear box is part of a solid casting that holds all the axles and wheelsets.

That can complicate the procedures for removing them.

For steam, the process is the same for insulating the left side wheels.

Engine (pilot) truck and trailing truck (if the loco is so equipped) wheelsets, are re-done like those for the diesels:

Turn down any over-size flanges and insulate the left wheels at their axles. Or, find 2 rail scale replacement wheelsets of the same diameter.

Re-fitting drivers from 3 rail to 2 rail is much more involved. This is because the locomotive's drive rods will provide an electrical contact to the left side drivers from the locomotive body and create a short circuit.

This means the left side drive wheels need to be insulated at their rims. 

First, the driver sets must be removed from the frame and marked on the side to be insulated.

A set of new tires with flanges meeting NMRA standard for 2 rail are cut on a lathe from seamless steel tubing for all the left side drivers.

The must be machined to the exact outer diameter of the right side (uninsulated) drive wheels.

The left side drive wheels and axle ends are marked to match their axle location for correct quartering when re-assembled, then they are pressed off their axles.

The right side 3 rail drivers have their oversized flanges (if so equipped) turned down to NMRA standard. 

The left side 3 rail drive wheels are each turned down to remove their flange and part of the rim, so the new driver tires will fit when pressed on with an insulating barrier between them and the driver rims. 

It is thin material, usually called 'fish paper.' The idea here is the same as insulating other wheel sets at the axle, in that the insulation is compressed somewhat to assure tight fit. 

The converted left side drive wheels are then pressed back onto their respective axles with exact quartering as marked.

Any slight change in quartering would prevent free rotation of the drivers when the rods are put on.

A quartering jig helps assure that all driver sets are in exactly the same quartering, even if slightly off from the original setting.  

This is a quick run-through of the process needed for converting diesels and steam locos from 3 rail to 2 rail.

There were some persons who used to do this work, but they are no longer available so far as I know now.

Ed Bommer  

 


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(@nyterm)
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Joined: 2 months ago
Posts: 45
14/10/2020 8:53 pm  

I forgot to mention that for all-wheel pickup from the rails, the insulated side will need contact wipers to complete the circuit to the negative side wheels.

For steam power, that is usually done by having the tender common to the left or negative rail and the insulated wheels on the right or positive rail. The drawbar is usually the negative connection and any detail between the engine and tender that touches both, such as a firing deck apron, it must be insulated. I used s short piece of black electrician's tape under the firing deck apron for that.

So much to remember in all this . . . . . 

Ed Bommer


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(@andy-estep)
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Joined: 2 months ago
Posts: 4
14/10/2020 11:30 pm  

Ed Bommer, 

Thank you so much for this well thought out and detailed descriptive reply. I really appreciate the time and thought you put into it. I am slowly working through the many challenging things that I see in O scale. I enjoy a challenge and the craftsmanship is what drew me from 3 rail O scale. Eventually I would like to build my own engines and cars and run them on track that I laid myself. I am working my way towards that goal with baby steps.

I have seen your modeling and I find it very inspiring. Thank you for your help.


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(@jwubbel)
Active Member
Joined: 3 months ago
Posts: 9
23/10/2020 6:56 pm  

Converting 3 rail diesels to 2 rail could be a great opportunity as an introduction for many considering O Scale 2 Rail as the primary scale to model. While at first blush it seems like an imposing proposition in terms of difficulty or exactly how to go about it and what to do, like anything else you take it a step at a time. Break the problems down into smaller ones.

In my case having been in 2 rail for many years, one of my desires was to build a fleet of GP-30 units for my CGW collection. It is easy to simply go out and buy the brass RTR engine and get a custom paint job on it, but that defeats the pleasure of building the model yourself. Thus, most of what I try to build I do in brass. But guess what? I have found it easier to get a plastic shell to either kit bash or mock up a model prior to scratch building it in brass.

This approach is not all that different for the entry level O Scale 2 rail modeler or anyone that is changing scales. I purchased on the cheap some Lionel GP-30 and GP-35 engine shells and started from there to build the underframe and floor structure with the fuel tank. Along the way solving some of the problems. While these Lionel shell underbodies look to be almost identical, there are differences in dimensions for developing the power truck platforms and components but not enough so that it is difficult to make modification in the CAD program. I took what I learned from working on the All Nation F units and applied them to these kit bash projects. The most nagging or nuisance problem of course is getting the body height to the rails and couplers just right since the tendency is for the body rides to high on the trucks. So all the factors have to be thought out for instance what trucks will be used, CLW, AN or perhaps P&D where the truck bolster profile plays a role in figuring things out. If I make a mistake or I cannot get to a finished operable model either non-powered or powered, I would not be unhappy since mostly my time is the only thing invested.

Once you get to a stage of an non-powered model, then you can start thinking about a control system, power on board or sound installations which is not much different than taking an old well oiled engine and upgrading. Same story but a different set of problems. And, it is not out of the question to get help from other modelers that are in the process of doing the same conversions. And, that means not having to rely on a commercial outfit to do the conversion for you.

Modeling railroads is a very visual activity and so working in the FreeCAD environment allows you to model in 3 dimensional space, rotate and size things up before creating the part. After working a little while on the CAD, one realizes that most everything to be modeled are primitive shapes readily available for use in the software. Thus, learning the moves to size, cut, chamfer etc. becomes pretty easy and almost mundane. From there you can take it to the 3D Printer and you are well on your way to completing a conversion.

John - CGW


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