The word Gleisersatzverkehr is an important word to know in German.  It means “hahahaha, your train’s not coming sucker.”  It also means “there’s construction on the tracks,” “your trip is now going to involve switching between several (slow) buses and trains,” and, literally, “track replacement traffic.” 

I was on my way to Esslingen, a little town (by little I mean approx. 90,000 inhabitants) on the Neckar.  But I was going there via Mannheim, where I could trade in my train seat for a seat in a beat up old police van (no longer owned by the police).  I took the train to Worms, did some transferring and bus riding to circumvent the construction on the tracks, and landed in Mannheim two and a half hours later.