7 1/4 inch is massive, and not a toy! I have experience with 5" gauge, and even at that gauge anything bigger than a small tank loco needs 2 people to lift them, and most people use a jacked lifting table to get locos between different levels - and you need to get it down to ground level so that means a lift installed in a pit or a crane-equipped trailer.
I would say join a club which has 7 1/4 and help someone who runs on that scale there to get a feel for the practicalities.
(Our club considered installing 7 1/4" but it didn't get anywhere, I believe aluminium rails are easy to handle but have poor adhesion and are expensive and pilferable. It is also a lot of work drilling every sleeper 4 times and screwing the rails down... you can buy Gauge 1 track pre-assembled.)
The other thing I would say is that I would be concerned that you might end up with a train that just shuttled up and down a short track: when you have a train on that scale you really want to go somewhere!
A
(Googling finds lots of stuff, but not as much as smaller gauges.
https://www.sevenandaquarter.org/sales-and-wants/?/Engines+&+Rolling+Stock/ has a single point lever at £40!)