The Real Ghostbusters: Series 5 (1989)

Egon accidentally gets caught in the Proton Beams along with a ghost. The results are horrifying, causing them to exchange aging processes. Egon begins regressing at an alarming rate and the Ghostbusters must reverse the process before he disappears into nothingness...Poso, an overstuffed ghost has a goal - to be the ghost-father of all ghosts. He succeeds in kidnapping Janine and Louis and demands a ransom from the Ghostbusters. In order to release the captives, Poso wants the Ghostbusters to surrender their equipment and headquarters...The Ghostbusters are stuck on a speeding train. In order to get it to stop, they must play and win a series of games...