Выберите предложения, которые содержат независимый причастный оборот.

1)The loco may have one or two diesel engines, their number depending on the locomotive duty.

2)The speed of shunting over the hump appears to be different in different yards.

3)The vehicles have been substantially improved, the most important advance being the substitution of steel, aluminium and plastics for wood in their construction.

4)The dispatcher controls his territory, the track diagram showing him the position of all points and signals.

5)The aim of controlling is to keep traffic moving freely.