Maybe a coaster hub would be possible, but the chainstays are pretty hefty so the clamp may not go round it.
Just ride it fixed. There's nothing sadder than a track frame with a freewheel on it.
@bq started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Maybe a coaster hub would be possible, but the chainstays are pretty hefty so the clamp may not go round it.
Just ride it fixed. There's nothing sadder than a track frame with a freewheel on it.