A faulty train caused huge delays for Victorian racegoers heading home from Derby Day, leaving them reportedly forcing open the doors to walk on the tracks.

Commuters on the Flemington-Craigieburn line said they were "packed like sardines" for an hour following the race on Saturday and dozens decided to instead brave the rain and walk home.

Metro Trains apologised for the delay, which it said was caused by a train fault and trespassers near the tracks.

Commuters took to social media to complain about the "hell" of being left "stranded", packed in carriages "like sardines."

One public transport user tweeted there were “People spewing and passing out in the train.”

Footage shows racegoers climbing out of the trains to cross the tracks and walk home.

Many claimed there were no announcements at stations about the delays, despite Metro Trains advising passengers to “Listen for onboard/station announcements.”

More than 87,500 people attended the annual race day at Flemington, many of which relied on public transport to get home.

Tens of thousands of Victorian racegoers are expected to pack Metro Trains again on Tuesday for the Spring Racing Carnival's flagship Melbourne Cup event, followed by popular Oak's Day on Thursday.