Without a doubt the most bizarre fact about the UK railways is that despite all of the different TOCs that operate up and down the country, all trains serving the busiest station are served by a single TOC (namely South West trains at London Waterloo)
Most I can come up with is six at Edinburgh Waverley (Scotrail, VTEC, VTWC, Transpennine express, CrossCountry and Caledonian sleeper)
Haymarket has the same six by extension and possible Glasgow Central as well (although I'm not sure whether VTEC still has services that run to Glasgow Central, or if the Glasgow sleepers run from Queen Street as opposed to Central)
Most I can come up with is six at Edinburgh Waverley (Scotrail, VTEC, VTWC, Transpennine express, CrossCountry and Caledonian sleeper)
Haymarket has the same six by extension and possible Glasgow Central as well (although I'm not sure whether VTEC still has services that run to Glasgow Central, or if the Glasgow sleepers run from Queen Street as opposed to Central)