Kingfish, you also hit the nail on the head... overhaul, rebuild, remanufacture... terms used in various industries without a consistent definition even within those businesses.
In my world, and that isn't railroads...
Overhaul would be to inspect, replace and repair common wear items exclusive of a block tear-down... gaskets, seals, belts, long service life fluids, cut off switches, sensors... especially those that have been upgraded by the manufacturer, specifically making the original parts obsolete. And finished off with a static or dynamic load test. I guess an analogy would be a 100,000 mile service on gas engine, including a timing belt and water pump change.
A rebuild would tackle the block, specifically rings, valves, bearings, and if so equipped, piston liners, cross-heads ... the parts that see friction wear as well as sulfur and water corrosion. Also throw in the slave items for replacement with other "rebuilds"... alternator / generator, air compressor, etc. And traction motor replacement. But in no way significantly alter the basic components or design criteria.
Remanufacture would include all the above, and a complete block tear-down, and now add the crank, electronics, head upgrades... up to and possibly including block changes, conversion from DC to AC...
I'm assuming running gear, brakes, wheel truing and replacement are covered under normal maintenance cycles. But I also assume that a specific task list is established between an owner and a shop, as the owner may opt for cheapest way possible, and the shop clearly wants to gold-plate everything... so I guess that's how Rome operated, you tell us what you want and we'll do that and nothing more, as opposed to Altoona who has a Chinese menu of packages but will specify a minimum amount of work prior to release.