Trailer's Bumpers' size

[nofar#1943]

Hello everyone! :)
Does anyone know what is the size of the bumpers of the trailer?
I've been searching it for hours...
I'll be thankfull if you find it to me. :yikes:

[NorviewsVeteran]

For the team drawing, it was 1/4" plywood, 16 1/4" long by 5" tall.