Continuity mistake: At the beginning, Edward is pulling 5 cattle trucks. When he approaches the cows, he is pulling 4 cattle trucks.
Continuity mistake: Gordon's express train has 1 composite coach and 2 brake coaches when he passes through Wellsworth station. When he crosses the viaduct, he has 2 composite coaches and 1 brake coach.
Continuity mistake: Gordon can be seen next to Edward when Edward says "two big engines afraid of a cow?", but Gordon should have been on the turntable.
Answer: He was in the water.