Sacon?

Ok so Thomas has been saying "Sacon" for weeks now... I have tried everything to sort out what he was saying. He would say it when he was playing, especially with all of his trains, also when we were driving down the street...Was just about to drive me crazy...He only has one more word I have no idea where he got it from "pdarsa" which is what he calls all money, coins and bills.. So we finally figured it out! "Sacon" is signal, and in all of his Thomas books they talk about signals and now when we are driving he thinks the stoplights are signals also. Whewww what a relief!
"sacon" = "signal"