Anyone know if we can take a scenic train for a day trip from Basel to see mountains?
Yes! Basel to the Lauterbrunnen Valley is about 2.5 hours by train. You’ll go through 🇨🇭 Switzerland’s capital city, Bern, on the way and pass Lake Thun.
Lauterbrunnen is a glacial-carved valley with mountain peaks to be seen everywhere.
You can, although none of the "scenic" trains call at Basel. You would have to take a train to one of their start points, but it can be done as a day tip.
Train to Spiez (probably with a connection in Bern), then a train to Zweisimmen and transfer to the MOB train to Montreux. That section has some trains with panoramic windows, At Montreux, you can take a fast way back to Basel that skirts the big mountains.
https://mob.ch/line/ligne-montreux-zweisimmen/?lang=en&_ga=2.252979467.302969992.1651366369-312153386.1651366369Train to Bern, then transfer to the hourly "Loetschberger" to Brig. That route goes through the Berner Oberland Mountains with one longish tunnel. Again, you could take a fast way back that uses a much longer tunnel that goes completley under the mountains.
https://www.myswissalps.com/lotschbergerCircle route by taking a train to Luzern, then transfer to a train to Interlaken Ost. That route has all-panoramic carriages and goes over the Bruenig Pass. At Interlaken Ost, transfer to a train to Bern, then a train back to Basel.
https://www.zentralbahn.ch/en/interlaken-express
PS. Each of these 3 trips will take 8 to 10 Hours to complete with a 2 hour lunch break half way. The cheapest way to do these will be with a Saver Day Pass. You need to buy it up to 60 days before you do the trip. The further out you buy it, the lower the price. Cheapest price is 52 CHF per person. Unlimited travel on Swiss trains for the day you purchase it for.
https://www.sbb.ch/en/travelcards-and-tickets/tickets-for-switzerland/day-pass/saver-day-pass.html