Another video of the rescue here, clearly showing that the leading bogie of the 375 is on wheel skates, as a result of the damage sustained during the derailment. According to the person who posted the video on youtube, the max speed was 5mph, due to the use of the wheel skates. The stricken 375s were apparently taken to Ramsgate.
https://www.youtube.com/watch?v=BHedP-1ySFw
Tony