There is a clear lack of connection toward France and Spain.
EDIT: Paris is of course well connected, but southern France and Spain are not. I live in Zurich and it's quite easy to go north, south, and east by train, but going south-west towards Marseille, Toulouse, Barcelona is really inconvenient. And it's not just about Zurich, because doing so from Milan or Frankfurt, I would guess, is the same. However I heard of plans for a Zh-Barcelona night train, does anybody know anything about it?
One cause is that France is rather obstinate when it comes to sleeper trains passing through, but not stopping in, France. A direct line from the Netherlands and Belgium to Spain (e.g., Barcelona) would be viable and possible on standard gauge, but it wouldn't make sense to stop in Paris at 2:00 in the night or so. SNCF and the relevant French agencies insist on trains serving France as well.
Maybe some company will manage with a perfunctory stop in Perpignan?
The train passes through France non stop. Along the way, around 2AM, a single carriage decouples from the end and smoothly glides into a Paris terminal, where it functions as a de facto hotel room for the night as guests won't be kicked out until morning. Will anyone use it? IDK. But it does satisfy the requirement of stopping in France.
You van already do Bruxelles to Perpignan with a direct ( french ) TGV train, in 6/7 hours. If you want to go to Spain I believe bruxelles Barcelona via Paris is also quite practical. Everything is much pricier than plane and no night train though
I've done Paris to Barcelona on a sleeper to Perpignan and an express from there. I think for people who like sleeper trains, a through service would be far more convenient, even if it stopped in Perpignan early in the morning.
I suspect there is not a lot of track capacity across the Pyrenees, though, which would mean the sleeper train would have to get in before the morning expresses start.
True. One of the issue is the different gauges. This used to be avoided by variable-gauge Talgo cars, and now by high-speed trains (TGV) on standard gauge on the Spanish side. But AFAIK there are no sleeper high-speed trains, and I am not even sure those Talgo are still running (and they also were not sleepers when they did run). So even in the best cases there could be connections but no direct services. Also, there will be only 2 possible routes because of these pesky mountains.
There are several ways to work around that though, and I think this will happen in the reasonably near future.
NightJet trains from Zurich to Barcelona and Rome were indeed planned to run from 2024, but this will probably be delayed because the Swiss Federal Railways won't receive subsidies they were expecting: https://www.srf.ch/news/wirtschaft/ausbau-des-nachtzug-netze... (article in German)
