A spate of copper thefts has hit the railways in Melbourne's west, forcing thousands of commuters onto buses on four of the past seven mornings.

Thieves stealing lucrative copper cables and vandalising the railways near Laverton caused Altona Loop services to be suspended or altered for more than 15 hours in the past week.

Railway officials say thieves are putting their lives at risk by raiding electrified areas in search of copper. Credit:Bloomberg

Commuters using the Altona Loop during morning peak hour have been plagued by 40-minute delays and forced to catch buses.

Nearly 50 buses have been ordered while trains were down on Thursday and Monday this week and Saturday and Thursday last week.