This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 輺 is uncertain. It combines 車 (vehicle) with a complex upper component that may be a phonetic or semantic element, but the origin is unclear.
With 車 (vehicle) on the left and a stacked shape on the right, imagine a specialized cart or carriage, but its exact purpose is unknown.
For シ, picture a mysterious vehicle that makes a soft 'shhh' sound as it moves: shhh -> シ.