Swiss passenger train sets record for length.
 

I got this off RT News which is probably banned in the UK, here is the text:

Swiss claim record for world’s longest passenger train

A Swiss railway company claimed the record for the world’s longest passenger train. The Rhaetian Railway company ran the 1.9-kilometer-long train along the Albula/Bernina route from Preda to Berguen.

The Swiss train nearly 2 kilometers long composed of 100 coaches will thus enter the Guinness Book of Records as the longest passenger train – a bold move, especially amid the energy crisis on the continent, which drove up costs for rail companies.

The Swiss Federal Office of Transport has recently began adjusting the pricing model for railway electricity to allow for a fixed price for at least four years. The initiative was taken with SBB Energy, the rail electricity supplier for Swiss Federal Railways (SBB). Furthermore, SBB has announced it will reduce heating in train coaches as part of measures to save gas and electricity.

I can't imagine that this was other than a one-off exercise. The logistics of operating such a service regularly don't bear thinking about!

It was set up as a special to mark an occasion.

Video here of it in action.

https://youtu.be/shVE-_KXYvg