# USA Trains F3 A and B units



## GarryNCGRR (Jan 18, 2008)

Just wondering if the USA Trains F3 A unit shell fits the B unit frame? I know the circuits are not the same ...but just wondered if the screw mounting holes are the same, and if there are any other things that might cause a problem getting an A shell to fit onto a B lower unit ?

Garry NCGRR


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## Michael Glavin (Jan 2, 2009)

Garry, 

I suspect the only difference of the A/B unit base frames is the radius of the nose verses the squared ends of the B unit and tail end of the A unit. If you must know 100% I can wander out to my shop and compare the two side by side. I have a couple sets of each broke down for battery, sound and smoke mod’s… 

Michael Glavin


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## Greg Elmassian (Jan 3, 2008)

Different number of screws, you might be able to cut down the B unit chassis to fit... 

Greg


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## GarryNCGRR (Jan 18, 2008)

Thanks guys. Those screw tubes could be a problem for sure....thanks

Garry


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## Michael Glavin (Jan 2, 2009)

Garry, 

It's all the same less the nose end of the base frame, as noted previously it’s rounded. At the nose end there are two less screws/tubes to hold the body to the frame. Looks like a "B" unit base frame could be modified to use with an "A" unit body shell.

Michael


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## Greg Elmassian (Jan 3, 2008)

actually the front 2 posts in the b unit are replaced by a single centered screw just under the leading edge of the front truck... 9 screws on the A vs 10 on the B if memory serves right. 

You can probably get away without that one screw.. 

Greg


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