This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
轃 combines 車 (vehicle) with 秦, which likely contributes the sound. The exact historical development is uncertain.
A vehicle 車 beside 秦, a shape associated with a place name or sound. Without a clear meaning, picture an ancient carriage arriving at the Qin state.
For シン, imagine the carriage's wheel spinning: spin -> シン, as the vehicle 車 moves forward.