multilayer train; train formed by joining sections with different origins/destinations
Technical railway term. Refers to a single train that is formed by coupling two or more trainsets that started from different origins or will split to different destinations. Not a double-decker train.
A multilayer train may be split at an intermediate station.
In this multilayer train, the front four cars are bound for Tokyo and the rear four for Shinjuku.
分割併合列車 is a more general term for trains that split or combine, while 多層建て列車 specifically emphasizes the formation from sections with different origins or destinations.
二階建て列車 means a double-decker train, which is a different concept from 多層建て列車.
Compound of 多層 (たそう, 'multilayer') + 建て (だて, 'building; structure') + 列車 (れっしゃ, 'train'). The term describes a train 'built' from multiple layers (sections) that have different origins or destinations.