Broke the attachment hook off the left hand point (the one I was filing). Part Number 610-2065-006.
It is unavailable from Lionel and I am not having any luck locating it. I'll post in the wanted section of the forum otherwise I will have to try and find another 048 RH switch. My fault for being careless.
EDIT: Called Lionel. They actually did have them and because I bought it directly from them they are sending me the part for free. They are great.