Just got to thinking about how it would make more sense for the first train ride from DC to NV cost a lot more than any subsequent train rides back and forth. Rationale here being that 200 years after the Great War, rail lines would be in poor repair at several places and it is very likely that scavengers would have removed some of the relevant rail track sections for their own projects during the centuries - So, the first train ride would need additional expenses to be paid, finally something substantial to spend some of that fortune of bottlecaps acquired during the capital wasteland storyline (my characters on most playthroughs - on hardcore/very hard - are often bottlecap millionaires by the time they get through most Capital Wasteland quests).
These first time additional expenses could include having to hire an entire scavenger team to repair/replace rail track sections by scavenging other rail lines not in use (this could take months or more), as well as a capable merc outfit (like frex Reilly's Rangers) to protect the whole operation from the dangers in between the two wastelands. Also, equipment, tools, spare parts, ammo for mercs and consumables for everyone for the hirelings would add costs. Requiring at least 10 000 caps (perhaps even 100 000 caps or more, or alternatively a sizable fraction of total caps owned by the Lone Wanderer) of extra payment for the first train ride (to properly establish the rail line connection) would seem perfectly reasonable. This extra cost would not be necessary on any subsequent train rides (which would have the usual costs of tickets), because the DC-NV rail line operation would have become self-sufficient by then (9 years later) and would be ran by someone other than the Courier 6/Lone Wanderer.
I don't really know that much about mod-making, but implementing an option of extra cost for the first train ride with a bit of explanatory text propably would not need much work - Just one extra text message box with explanation and a choice to either pay the extra cost to fix the rail line to full operational status in order to make the first journey or do nothing and leave (And this extra message box would only appear for the first journey). As for why to implement an option like this, I think it would add immersion and perhaps even a certain sense of accomplishment for the player to see the Lone Wanderer's hard earned wealth to have such a direct impact on the gameworld of TTW.
Of course, this is just my personal opinion, I think that the first journey is perhaps a bit too easily affordable. What do you all think would be the best way to assign costs for TTWs first train ride?
200 years ago there was no caps as a currency, the station in DC has been sealed since the bombs fell down, so it would make sense the tickets cost pre-war money 
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