Ridgie Jumping

Breaking into the guard carriage of an old Australian NSW suburban train and jumping off the back of the train into the train tunnels. The train is generally a C-set or a K-set.

John: Hey man, feel like doing some urbex
Sam: yeah ok sounds good
John: let's do a ridgie jump
Sam: Yeah man, ridgie jumping sounds good, I haven't been in the train tunnels for a while, let's do it!