Oh no, you mentioned trains and this causes me to post again!
I used to use train fares as a justification to fly.
So I’d find out how much it would cost to get there by train.
Then I would estimate the amount it would cost to fly there.
Subtract the train fare from the flight cost and divide it by the flight time and you fly cheaper...
Then there was the time I had to visit Bournemouth Hurn to look at Airbus 310 wing leading edges.
The Condor has a 3.3 litre engine and so I got something like 15p a mile petrol allowance. Good enough, I drove to Redhill, flew to Bournemouth, and night stopped there. The Condor slept in the hangar under a BAC 1-11.
Next day I was to drive to Chester, but instead, flew back to Redhill, took a day off, and then took the trusty Viva HA up there. The miserable lot at Hawarden wouldn’t let me commute into the airfield so they could bloody well wait for my services.
I bought a Spitfire MKIV so ferried the Viva back to Redhill. Costed out the train to Chester, and deducted this from the cost of flying TLB back, and having a friend return the Jodel to the Tiger Club. ‘Landed in a farmer’s field, hopped the fence, walked a quarter mile into work, and did some overtime, it was a Sunday
You can always find an economic argument for your passion.