Just worked over this chord from the Windsors onto the joint NR/District line between East Putney to Wimbledon. What services actually use this line? LO? The rails are shiny, so it definitely sees some use.
Mainly SWT ECS, with a handful of passenger workings:
2L10 04 54 Basingstoke - Waterloo
5C07 05+05 W’don Pk - Waterloo
5O05 05+19 W’don Pk - Waterloo
5C09 05+34 W’don Pk - Waterloo
5Y81 08+21 Waterloo - W’don Pk
5Y93 08+58 Waterloo - W’don Pk
5Y83 09+14 Waterloo - W’don Pk
5Y87 09+26 Waterloo - W’don Pk
5Y84 10+36 Waterloo - W’don Pk
5Y86 10+48 Waterloo - W’don Pk
5Y90 11+04 Waterloo - W’don Pk
5Y85 11+36 Waterloo - W’don Pk
5O96 16+38 W’don Pk - Waterloo
5Y95 23+43 Waterloo - W’don Pk
5Y88 23+50 Waterloo - W’don Pk
5Y89 00+20 Waterloo - W’don Pk
2K77 00 42 Waterloo - Strawberry Hill
1B01 01 05 Waterloo - Southampton Ctrl
That's from Dec 2010 - probably still about right - and there are also 'Q' paths for transfers from Clapham Yard to Wimbledon Park.