Hi John – interesting thought, but this model is pretty heavy, and unless the rear axle was strongly sprung, I think it would teeter around the middle axle, and maybe pop a wheelie when it started up. Plus it has the one piece rods as supplied in the kit, so they would need to be altered. Once you get that far you are perilously close to throwing it away and making a new chassis!
I am still tempted by the capacitors though. I suppose the difference to DCC is that the loco is not under your control – the run on will happen regardless of what you want it to do, which might be an interesting replication of the momentum involved in driving a real engine.