Berlinwalk.com · Free tool
A U, an S, an M and a three-digit number all sit on the same map. Type any line label and I will tell you exactly what it is, whether your ticket covers it, and when it stops running.
Tip: the letter in front of the number is the whole secret. U and S are trains, M is usually a tram, and a bare three-digit number is a bus.
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