I am very supportive of the trains, they take people off the roads I want to use. Only on Tuesday a colleague and I had a a "race" to the Grant Thornton offices in London (Zone 1, near Moorgate)for a 0930 meeting. We started at Watford where we were hotelling it due to a meeting on weds.
He took the "fast" train and tube, plus a 5 minute walk either end. I took the Swede He arrived about 30seconds before I did, looking like he had taken a shower in someone else's sweat. He paid £23 for a return ticket plus zone 1 tube. My parking was a hefty £24 at an NCP 75yards from the office.
For me, a cost of £1 (plus a few quid in fuel) and 30 seconds was worth the comfort and relaxation of my own personal space, even had the company not paid my parking.
this experience mirrors what I found when I worked in London for 18months. If you took a bit of care about where you parked and used door to door times rather than TFL fabrications, there was basically nothing in it, either cost or time wise.
However, I do acknowledge that this would not be the case if everyone thought as I do. These days, if I were in central London I'd buy a motorbike (and learn to ride it).
Where I do think rail has a place is for "inland ports" where you can ship entire trains of containers at once and relieve the choke points around out major freight ports.