A number of Brio pieces my parents kept around from my childhood have seen better days— missing pieces, cracked smokestacks, and broken knobs on track pieces. My most recent repair job was this arch bridge (333631).
This is not the viaduct that came in many of the classic figure eight sets, but a two piece bridge, and in my case missing both male pins. I recall it being broken even in my own childhood, and there was dried hot glue on the ends where my father had clearly tried to make it work for us anyway.
The replacement pins came from TrainLab on Etsy. I didn’t have a metric sized drill bit set, so I had to work at it with a slightly smaller bit- I was a little worried I might crack or break the piece drilling out the broken pin, but it ended up being just fine.
So far my son is not quite as impressed with me as I am, the key takeaway I got (as only a two year old can tell it) was that I couldn’t use it because Nia (his favorite Thomas character) couldn’t fit through the tunnel.