On Earth, the Great Western Railway employed 'slip coaches,' which were passenger carriages where the coupling hook could drop away. A brakeman in the coach would then use a brake to slow the coach to a stop at a station, thereby letting passengers off without the main train needing to stop.
Obviously this practice was abandoned for safety reasons. But Kerbals don't have such concerns.
So Kerbals, of course, operated slip coaches on some of their passenger rail lines.
But one of the stated benefits of the space program is that it provides spin-off technologies to improve Kerbal lives and industry here on Kerbin, not just in space.
Consequently, Kerbals began employing "reverse slip coaches," where a coach would rest in a siding off to the side with a protective wall between the siding and the passenger station. When the train passed, it would, with precise timing, fire rocket motors provided by Periapsis Systems of 'sepratron' fame, to accelerate the coach up to speed, so that it could couple onto the passing train. It was a tremendous success! *
