Frazer: Sorry about the candles. The blinds are a bit thin for the gleam of the gas light.
Godfrey: Oh, I like candles. They're more romantic.
Mainwaring: In the words of the great E.C Cochran. "Early to bed, early to rise, no jolly good if you don't advertise."
Godfrey: Sir. I wouldn't want to roam the countryside ravishing maidens.
Frazer: I am refusing to obey.
Mainwaring: You'll be in charge of the liquor permits, Frazer.
Frazer: I'm right behind you, Captain.
Pike: I'll tell mum.
Godfrey: Oh I do wish that Captain Mainwaring would let my sister Dolly knit him a suit of armour.
Frazer: Never mind Godfrey son. If anything goes wrong we'll get him out with a tin opener.
Jones: You know, when I was in the Sudan.
Frazer: I never doubted you for a minute.
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.