No need to go inside fence, although you'll come pretty close.
South side of train (side closest to the tracks!), on the CABOOSE. Low, no need to climb on train but you will likley have to crouch down.
PLEASE NOTE: There has been some confusion about the type of cache container... the one we hid is a Magnetic hide-a-key box but there have been multiple caches at this location that went "missing" and were archived so it seems at least one of those containers has resurfaced. You may find a different container type or maybe even multiple containers.