Continuity mistake: The platoon's rifles have no fore sight at various times in this episode, at other times they are fitted. Most noticeable on the railway platform and the march to camp (missing), but when they arrive at the camp, all the fore sights are on. They are missing during the outdoor training scenes - and they are missing from the credits at the end of every episode when the platoon members are shown in close up (these shots were from this episode). (00:09:00)
Other mistake: When the train stops Godfrey gets off to relieve himself but when he is climbing back in to the carriage the train appears to be already moving at speed because the background projection started moving too early.
Other mistake: Walker is attempting to steal items from the farm but appears on the training activity with the other troops at the same time.
Answer: The show is a comedy, this was played for comedic effect and to show that in times of extreme fear, in this case about to be crushed by a steam train, the men had an adrenaline surge strong enough to pedal fast enough.