When did they start to move the running rail out at Chester racecourse?

Question

Horse racing

Answer 1

normally at the chester may meeting,they will push out the rails from the 2nd day,in which the actual advertised race distances are slightly longer.

they also do this on oaks day in which oaks runners actually cover more ground then the derby horse over the same disatnce even though both are advertised at 1m4f10yds.