AF Big Boy Truck Modifications for S Gauge Dimensions

Finished Big Boy with trucks narrowed

 Modification to front tender truck and trailing truck frames and centipede 
truck sides narrowed from O Gauge to S Gauge width.

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Factory AF Big Boy tender Lead truck originally a K-line O gauge truck refitted with S Gauge wheelsets by Lionel for the BB.. Tender truck frame width reduced by 3/8".
Wheelsets axle length custom cut and 
needle points ground to fit each truck

Width reduced by 3/8" by cutting and milling

Sides are held on with 4-40 cap screws

Electrical pickup fingers fabricated and installed.
Stock AF Big Boy Loco Trailing truck Loco trailing truck frame width reduced by 7/16".  Wheelsets length custom cut and points ground to fit each truck
Width reduced by cutting and milling.
    Assembled with number 2 hardware

Before mods. sideframes were odd looking 

 Finished and installed. Looks much better!

Razor saw cutting. Milling setup.
The Centipede trucks have been removed from tender shell by sawing off with a saber saw and dressed up  for mounting inboard on the tender frame to be S gauge width.

The tender shell is wrapped in protective tape.


Side frame mounts fabricated from aluminum. Sides are CA glued to mounts .
Sideframes assembled and painted. The mounting holes use existing screws on the tender frame 

Before Mods. Truck frames hang way outside the rails

Finished tender looks like it belongs on the track now with both sets of trucks re-gauged
. Alignment with rear wheels is aligned sideframes now. Doesn't look quite so boxy now either.