How do the repeat, track-move and locomotive-score factories work?

Question

Accepted Answer

The factory that repeats an action works like Engineer 8 and needs a space holding exactly one worker. The factory with two track advancements gives two single-space moves on the same or different tracks. The factory that scores your two best locomotives pays when the marker lands, not at round end.

Russian Railroads

How do the repeat, track-move and locomotive-score factories work?