Plunge into

Before asking the reader to plunge into the subject of linear models I shall, in accordance with a sensible custom, attempt in the few pages which follow to give some idea of what this subject is.

At 0508 on July 18 1981, the last freight train plunged into the 3-mile 66-yard Woodhead Tunnel at Dunford Bridge. [...] As it emerged back into the daylight at Woodhead at 0514, heading west, that was it for this famous railway line.