# A-1-A Trucks



## harvey (Dec 30, 2008)

About two years ago now I started to build some GMD1 locomotives, but as some will know these became stalled for quite a while to allow me to complete some other projects. Now I'm making another effort to get these completed.
In order to do so I needed some A-1-A trucks and as far as I know none are commercially available and so I needed to make some. Lucky for me and all others in this hobby we have USA Trains and their parts department, they have been a tremendous help in providing the parts I need to move forward with this little project.
The trucks I used are their standard trucks supplied for their GP9's and this what I used to chop up extend and generally modify beyond any original identity.

This where I started.









This is small jig used for spacing the axle centres. It will be noted that the centre pin is lower than the two outer pins this is to allow for the smaller centre wheel which in full scale is 34 inch whereas the outer wheels are 40 inch.









Here we can see what I had to do to extend the motor blocks. The ends were cut off and a 0.400" spacer added at each end.










In this photo we can see that the trucks have been extended, but still no centre axle. The truck on the right has the 40 inch wheels installed the wheels on the left truck will be used for the centre axle.









This photo shows the extension of the gear drives along the existing shafts. These have been moved out 0.200 inch at each end. On one of the older version of these trucks (motors) I found the shafts where a little shorter so I had to make sure I used only the later motor version.










More to follow.
Cheers.


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## Greg Elmassian (Jan 3, 2008)

Will be looking forwards on how this progresses, please lots of pictures.

Greg


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## jokensa (Dec 4, 2014)

wow!

can't wait to see more!


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## Ted Doskaris (Oct 7, 2008)

*GMD1 loco both 2 axle & 3 axle versions*

Harvey, 
Thank you for sharing such a great project.

It looks like the prototype GMD1 loco was made in both 2 axle and 3 axle versions.

2 axle GMD1 loco:











3 axle GMD1 loco:










Are these like the one you are emulating?










It's interesting how the center line of the middle axle is lower than the outboard axles just as you are modeling, so the prototype must have a smaller wheel diameter just like you are using.

Great!
-Ted


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## harvey (Dec 30, 2008)

Hello Ted, you are correct, but I'm not sure if CN ever took delivery of the two axle Flexicoil truck from new. I know they did later convert all of them to A-A trucks and used a larger fuel tank. You will also note that the A-1-A truck had the sand boxes at the end of the frames, although in one of the photo's you posted the A-A truck also had frame mounted sand boxes. In speaking with some retired engineers these were a real pain not only to fill but there was never any sand left when they needed it. 
Mine will have the sand boxes on the frames as all of mine will be of the NAR type and they did not get converted to B-B trucks until CN took them over. CN relocated the sand boxes into the hoods which allowed an increased capacity.
It's interesting to see that some of the GMD1's that CN has sold have ended up in Cuba these have the B-B truck on one end and A-1-A truck on the other!!
As I previously noted the centre wheel is smaller and is not powered.
Thanks for the photo's and the information.
Cheers.


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## harvey (Dec 30, 2008)

This is a little update on the truck progress.
The motor blocks minus the motors needed to be machined to take the third axle. This is actually an axle stub as the motor sits too low to allow the axle to pass right through to the other side. Of course this is off set as the centre wheel is smaller. The motor block at this location is also wider than where the original wheels are located so I had to machine a recess for the wheel to fit into and maintain gauge. I know it looks messy at this stage, but with three wheel sets installed the trucks seem to have no problem negotiation a USA Trains #6 switch. Hopefully this will be case when mounted to the engine frame. 
I made a short sleeve for the axle to fit in and this seems to work alright.










I should have posted this earlier, but this photo shows the alignment of the axle box after the spacer was installed.









This picture shows the motor installed in the extended motor block.










I made these dummy axles to satisfy myself that the alignment was alright. 
The centre bolster is a standard USA Trains supplied item, but I cut off the leg extensions as I need to mount this in a different manner. I now have a third axle there instead of a leaf spring assembly.
Also on this assembly I tried grinding more brake clearance for the wheels, I should have known better as they looked awful, they were eventually cut off and replaced with shoes giving a realistic clearance.










This photo shows a preliminary side frame overlay which will be used to reinforce the original frame which has been drastically cut away and will also carry the end frame sand boxes.










More to come.
Cheers.


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## Greg Elmassian (Jan 3, 2008)

What glue did you use when extending the motor block? It seems that motor blocks are usually made of slippery plastic.

Greg


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## harvey (Dec 30, 2008)

Hello Greg,
Originally I used a two part epoxy, but as you say the chemical makeup of the original motor blocks does not bond very well with epoxy as I found out immediately after dropping an assembly. I've been using contact cement as this has worked well so far even with impact on the floor. However, I intend to look around to see what options I have when I bond the outer frame to the remains of the original USA Trains frame.
Good question, 
Cheers.


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## Scott (Jan 29, 2008)

Coming along nicely Harvey, love the work you are doing.


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## NZRDa63 (Sep 1, 2012)

*A-1-A trucks*

Hi Harvey,

Re the A-1-A trucks : We thave these type of trucks in New Zealand 

They were fitted to the export model of EMD G-12's. 

The A-1-A configuration means the two "A"s (outside two axles) are driving axles and the "1" is an idler (non - powered, weight carying only).

Those sideframe on the Canadian National "1070" (further down in the thread) look exactly like the "Dofasco" trucks underneath the G-12's that had the A-1-A trucks. 

It might interest you to know ( if you didn't know already) that "Dofasco" and "Canada" are cast into the sideframe as well as this number 6933006.
I don't know what the significance is with this number, maybe a drawing / pattern number ?

Hope the above helps.

Let me know if you'd like any more info 

Cheers David


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## harvey (Dec 30, 2008)

Hi David,
Thanks for the info on the New Zealand Railways use of these trucks, I wish I had known this last year as I could have dragged my wife over to the railway yards to have a look with me, I'm sure she would have loved to have had some of these truck photo's in our vacation album!!
The Flexicoil trucks here in Canada do indeed have Defasco logo cast on the side frame along with CANADA and in some cases the pattern number. I'm not sure if the drawing I have has this information on as well I'll have a look at the next opportunity.
I'm afraid the trucks have taken a second place to the locomotives at the moment as I'm trying to get those moving forward a little faster.
Thanks again for the info.
Cheers.


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## NZRDa63 (Sep 1, 2012)

Hi Harvey,

I've sent you a PM 

Cheers
David


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