Yesterday I was returning home on one of the LM B'Ham/Crewe services from Euston. It was a little more "shaky" then usual, however when we were approaching Milton Keynes, the trains rocked quite violenty and we all assumed for a few seconds that the train was going to tip-up and there was quite alot of panic through-out the carriage. Obviously this didn't happen, but it was quite scary. Is it "normal" for a train to rock like this? It wasn't even windy.