The unprovoked assault happened at around 7.45pm in East Dunbartonshire on Saturday.
A large group of teenagers had just got off the train at Milngavie station when they launched their assault.
The boy was knocked to the ground, kicked and stamped on, leaving him with several injuries.
He suffered multiple cuts and bumps to the head - one of which required five stitches - and a black eye.
The male and female youths are described as being in their mid to late teens.
Anyone with information is urged to contact British Transport Police by sending a text to 61016 or calling 0800 40 50 40, quoting reference 552 of November 4, or contacting Crimestoppers anonymously on 0800 555 111.