Taking The GGB (Gornergrat-Bahn/The Matterhorn Railway)

The GGB Gornergrat-Bahn is a truly spectacular rack railway that operates between Zermatt (see MGB lines) and the highest open air station in Europe at Gornergrat.
The GGB station in Zermatt is across the street from the MGB station, where the trains from Brig and Visp arrive.
A Step-free transfer is available between the two stations.

As its colloquial name implies the line offers spectacular views of the Matterhorn mountain.
The mountain railway scenes in the TV series 'The Night Manager' were filmed on the CGB.

Also the end of the line at Gornegerat is a fabulous destination in itself, with views over a glacier, which can't be seen from the train; while on a clear day no less than 24 other mountain peaks can be seen!

The route is only 9km in length, but there are spectacular views available for pretty much the entire journey,
Though for most of its length the railway clings to the side of a mountain, so when ascending, the overwhelming majority of the views are on the right-hand side when facing forwards, though it can be good idea to tack a backward facing seat on that side of the train when boarding in Zermatt and to face forward when heading down from Gornergrat.
Most passengers will want to sit the other way round, so doing the opposite can make it easier to find a spare seat(s) with optimum access to the scenery.

It's also a journey of four distinct phases:

1. Until after Findelbach station, you'll be looking down on Zermatt
2. After Riffelalp station the railway ascends above the tree line and between there and Riffelberg is a dramatic birds-eye view down a valley, with the Matterhorn peak on the left, though you'll need good visibility to see this part of the journey at its best.
3. The Mattherhorn itself dominates the view between Riffelberg and Rotenboden, though the mountain is some way off in the distance.
4. Then between Rotenboden the view is of the mountains on the other side of the valley, which houses the glacier.

With the price of a round trip from between Zermatt and Gornergat priced at 120CHF, which equates to more than €100, it's an understatement that GGB tickets are fairly expensive, particularly as when ascending the journey only takes 33 minutes.

Though a 30% discount can be obtained when booking through tickets to Gornergrat at SBB stations and travelling via Visp on a combination of SBB, MGB and GGB trains
Tickets between SBB stations and GGB stations can be booked on the SBB booking service.

Though if you can book ahead for a day return journey to Gornergrat from a Swiss city it's likely that a Saver Day Pass will be a cheaper option

Eurail – no discount
InterRail – no discount
Swiss Travel Pass = 50% discount
Show you pass at the ticket office in Zermatt to obtain the discount.
Saver Day Pass - no discount if you paid the full price of the pass, 50% discount if you have a Half-Fare Card, so booked the Saver Day Pass at the Half-Card rate.