There was a hack.
I got tickets from Zurch to Tirano on the Bernia express for £40 each. You buy them from the German operator. Debahn.
You get a ticket from Siegen (sp) to Tirano with a stop in either Zurich or Chur. I went Chur. Make sure the departure from Zurich is to late to travel in one day and you have a stop over and pick the church train up the next day.
He explains it on his site. So all my Swiss travel has been cheap as chips.
You have to reserve a seat on the Bernia express seperately. That was £30 each.
So far I've spent £250.