Just a note on roller bearings:
It was actually almost twelve years earlier than I remembered that US railroads actually did their first serious experiments in all roller bearing locomotives. I thought it was not till the early 1940's but in reality it was 1930 when US manufactures finally followed European practice:
This taken from Wikipedia:
Timkin 1111Timken chose a 4-8-4 on which to demonstrate the company's bearings so the locomotive could be used in all types of railroad work, especially on heavy freight and fast passenger trains. A total of 52 different parts manufacturers agreed to supply their parts for the locomotive "on account" until the locomotive operated over 100,000 miles (161,000 km). The suppliers' names were placed on a plaque that was fastened to the tender for the duration of the demonstration period.
Assembly took place at Alco's Schenectady, New York, plant.
I do not recall just when roller bearings finally became standard equipment on all US built rolling stock but I would hazard a guess that it was not until the early sixties.
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