the 420s were the backbone of many public transport systems in Germany. I don't know how many times I took the S6 from Stuttgart Rohr to the University.
However, they were orange/cream at that time.
I remember very well the week when most S-bahn trains were grounded and the Stuttgart public traffic collapsed. The reason for this was pretty stupid:
Most trains had to turn at the Schwabstrasse station. To simplify the process, there was a very tight loop so that the drivers wouldn't have to walk to the back of the train. It was an exciting (forbidden) adventure to travel the loop This loop was so tight that a wheel flange lubrication system had to be used to avoid excessive flange wear. The DB had a huge supply of lube for this system. Nobody noticed that the grease had deteriorated over time. As a result, the flanges of some 2/3 of all Stuttgart S-Bahn trains were out of acceptable spec within a week.
Trains from all S-bahn systems in Germany had to be redirected to help out in Stuttgart.