急げ、さもないと列車に乗り遅れるよ。

really; extremely; in that way

not; emphatic suffix

if; when; and; with; particle used for quoting (with speech, thoughts, etc.); quoting particle; promoted pawn; indicates question (sentence end)

train (ordinary)

at (place, time); in; on; during; to (direction, state); toward; into; for (purpose); because of (reason); for; with; by; from; as (i.e. in the role of); per; in; for; a (e.g. "once a month"); and; in addition to; if; although

to miss (train, bus, etc.)

indicates certainty, emphasis, contempt, request, etc.; used when calling out to someone; used to catch one's breath or get someone's attention; yo!