Last train，可以翻译为“最后一班地铁”，是Jeff Meckstroth发明的一种表示满贯兴趣的约定叫，该名字来源于一首流行歌曲 Last Train to Clarksille. 以下摘自Wikipedia：

Last train refers to the bid just below game level in the agreed suit. Such a last train bid is typically made in a bidding in which one of the partners has denoted slam interest.

Any time there is only one call that indicates slam interest or further slam interest without raising the partnership’s level of commitment, it is a Last Train slam-try, unrelated to the strain named (unless followed by an uninvited further action).

Examples

1H 3H
4C 4D(*)

The 4D bid suggests to partner extra values, inviting partner to consider slam exporation.

1S 4D
4H(*)

The 4H bid asks responder to consider bidding slam with extra values (4D is a splinter bid showing 4+ Spades)


Last train Cue-bid并不承认所叫花色有“货”，只是表达：Hi partner，俺还有额外实力（可能是控制好、牌型好或点力高），但还没强到可以安全越过成局定约。