I'm trying to remember the name of a book, because I feel I want to re-read it. The book follows a group of squaddies and in the only scene I recall they are recalled to barracks. A 'Scale A' recall. They race to a train station and those that get there before the train leaves hold up the train for the rest. There is a verbal altercation with a train conductor. They are then - I think - sent to defend a British Overseas territory.