auto-train
/ˈɔːtəʊtreɪn/Chiefly US
noun
1Also with capital initials. A train which transports motor cars together with their drivers and passengers; a rail service of this type.
- A trademark in the United States..
2A road vehicle consisting of a series of linked trailers or passenger cars pulled by a lorry or other motor vehicle. Compare road train. Now rare.
Origin
Early 20th century (in an earlier sense). From auto + train.