To make replacement driver axles, two possibilities being thought about are: turning down surplus 6-1/2" x 12" roller bearing freight car axles to the required 6" journal diameter (the freight car axle journal surfaces would be removed before machining, as the axle ends will be flush with the outer hub of the driving wheel center); or, using 6-1/2" diameter blanks of 4140 steel, turned to final dimensions.

The reclaimed freight car axles have the advantage of being forged material, and probably readily obtainable.

Thoughts?

Howard P.

The reclaimed axles ought to be just fine, and cheaper, too.

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Never occurred to me that car axles would be larger than locomotive axles.

Believe it depends on the size of the locmotive.

If it was me I would prefer to use fresh material with a known pedigree.

"Surplus" axles are probably surplus for a reason. Maybe cracks, maybe the lab analysis of the metal shows it didn't meet the specs ? Maybe it was in a wreck and is bent slightly.

Not sure anyone takes a perfectly usable in spec freight car axle and makes it surplus for no reason.

If you find some where the wheel seat has been machined down below limits (if there are limits for that) and nothing else was wrong that might work, but it may not be any cheaper that fresh material.

A sound axle is kinda important in preventing "train wrecks", would be the last place I would try to save some $.

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Kevin has a valid point. Locomotives in preservation, particularly large ones, require and deserve good metal in their driver axles. There is no longer any desire to wring ton-miles out of a depreciated asset at the lowest possible cost; we had a similar discussion about 1361's boiler before good management cut that Gordian knot.

I would suspect that the source of 'condemned' axles for machining would be wheelsets with bad journals (as that portion of the axle will be cut off and melted for scrap) and there would be careful NDT to detect any cracking defects both before and during any machining to locomotive shape.

An alternative would be to use 'axle' steel as a source -- melt it and do a proper statistical chemical analysis of its composition, then cast it into an appropriate piece, perhaps NNS or centrifugal, and then forge appropriately. To me, that would be little different than specifying the alloy composition of new metal, and presumably less expensive, without sacrificing integrity. Not all operations can afford the Union Pacific style of aircraft-grade documentation of every component, and perhaps at railroad factors of safety a full aircraft-grade parts tracking can be overkill.

The manufacture of a railway is a complex process. Casting bloom to proper alloy, cutting to size, forging to proper length and diameter with seats, rough turning, heat treatment, rolling fillets, machining holes and centers, more heat treatment, finish grinding, NDT for surface and sub surface defects, sterilization, and final inspection. The quality of a used railway axle would be far superior to bar stock purchased from the local steel supplier. As I recall most axles are scrapped either because the roller bearing seat is under sized, or there is damage to the exposed portion of the axle from foreign objects. Best plan would be to get used axles from a wheel shop where they could understand what you need and they could tell you why the axle was being retired.

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And how many groups with surplus axles have followed those AAR rules before throwing leftover axles in their scrap pile...

Hmmm.

I'm almost tempted to tell you to call up Standard Steel in Burnham, Pa. (founded as Freedom Forge in 1795 on the site, later a former subsidiary of Baldwin, now a subsidiary of Nippon Steel & Sumitomo Metal Corporation) and ask them if they can make you new axle stock affordably. I believe they're the only source of forged rail wheels and axles domestically.

Wouldn't 4140 commercial bar stock still need to be heat treated and tempered to be suitable as an axle?