S10E12: Toby's New Shed

At Arlesdale End, Toby’s shed roof is leaking. Thomas thinks it would make Toby most happy if the roof was fixed, and so gets down to sorting out a new roof being built for the Tram Engine. But to Thomas’ surprise, upon Toby’s seeing the new roof, he is most distraught. What could possibly be tugging at Toby?