Hi Usman,

In brief, yes and yes.

4 days in 1 month is what is known as a flexi-pass; you pay a bit more for your travel days, but in practice you get better value most of the time because you don’t have to use them consecutively, so none of them go to waste. From the day you activate your pass you have one month in which you can travel on any four days. So in your case you could use two days to get to Switzerland (though a one day trip is possible if you’re starting from London or nearby), and two days to get back a week or several later.

If you’re British you are indeed European, including for the purposes of Interrail (so buy this, not Eurail). Shortly after the Brexit vote our rail companies tried to pull out of the scheme in order to try and coerce foreigners from mainland Europe into buying a more expensive standalone Britrail pass, but there was quite rightly a massive outcry over this and they had to abandon their plans.

There are/were still various countries that are not EU and participating in the pass-scheme, like f.e. Turkey. Note that esp. EuroStar and also all french TGV-and even more those direct to DE and CH, hefty SURcharges and obligatory SEAT REServations must be made- and these can add a lot to the total outlay. To avoid that you coudl travel via Brussel/BE and then Germany, these ICE trains can but do not need to be reserved. Then -as any train you boarded before 24.00 can be used on 1 travelday-you can reach BselSBB in 1 day using the overnight from Köln=Cologne.

Great amazing. Thankyou for the help

lastly whats the quickest route from uk to switzerland and back?

Technically the fastest is to take the Eurostar to Paris and then a TGV Lyria onward to any of several major Swiss cities, but as mcadv points out this constitutes really poor value with a pass, as the obligatory seat reservation fee for the TGV is obscenely expensive.

The fastest sensible route is to take the Eurostar to Brussels (€30 reservation fee in 2nd class, €38 in 1st with full meal included), then an ICE to Cologne, then change onto another ICE which goes to Basel. The ICEs don’t require reservation, but if you want to guarantee a group of seats with others in your party you can make them for €6 each at bahn.com (click “seat only - no ticket” at the bottom of the details box on the main booking screen).

I can’t remember off the top of my head how many of these ICEs from Cologne continue on to Zurich (and possibly also Chur), but once you’re in Switzerland it doesn’t really matter as there’ll be very regular trains that can get you absolutely anywhere in the country.

€4 (2nd class) and €5.30 (1st class) per journey, which can include multiple trains.

Thankyou very much for the info guys amazing. 
and can anyone tell me which train journey goes through the scenic mountains which isnt a super fast train?

Thanks for the correction - this is a really pertinent reminder to book these particular reservations from bahn.com rather than the Interrail app (which is where I got my innaccurate €6 figure from). So not only do you pay less, but you also get more!

There are a variety of Swiss scenic trains you could try, and as many of them are narrow-gauge they are most assuredly not super fast!

If you can get to or from Switzerland (or both ways) in only one travel day rather than two - or if you buy a slightly larger and better-value pass - you’ll still have one or two travel days left to spend on these scenic trains, which will be very worth having as ordinary tickets for them can be expensive in line with most other things in Switzerland.

I won’t tell you everything about the trains because half the fun is in finding out about them yourself, but there are the very famous routes like the Glacier and Bernina Express (which can also be done on regular trains without expensive reservations), and lesser-known gems which @seewulf, @runner.on.rails, and quite possibly others have written about on here, like the little trains that potter around the Appenzeller Alps in the northeast. If you don’t have much time, a short stretch of mountain railway like the Zentralbahn might be a good option - it links the picture-perfect historical city of Lucerne with the activity-oriented lakeside resort of Interlaken, and if you want to go further it forms part of a longer train journey onward to Montreux called the Golden Pass route. There are also services over the scenic old north-south mainlines which have now been bypassed by base tunnels, like the BLS train over the Lotschberg pass and the Treno Gottardo over the Gotthard pass - both of these take you south towards Italy.

As @EdM  already said the Routes of scenic trains in Switzerland are endless :)

The questions is do you wanna go in one day from London all the way to switzerland?
Currently the earliest Eurostar arrives in Brussels at 12pm means you are at 10pm in Zuerich (with luck at 8pm) Maybe break the Journey already in Cologne

or catch the Eurostar to Amsterdam and in the evening the Nighttrain to Basel/Zürich just for the adventure Zürich is a good base for day trips by rail across Switzerland.

For example the mentioned Train Gottardo via the old hill line to Loccarno then onwards to Domodossola and via Brig - (Kandersteg) - Bern back to Zuerich
Here you have 3 scenic non superfast trains in one day :)

Other routes are you may consider is Zuerich - Chur - Tirano (from here the Bernina bus to Lugano IR Valid)  or by Regionaltrain to Milan :)

From Lugano back to Zuerich once more you can catch here the old hill line or the new base tunnel

Here a not finished list :D