Extreme weather testing saw trains that will soon hold Welwyn Hatfield and Potters Bar’s commuters subjected to -25c temperatures.

Welwyn Hatfield Times: An ice encased train in the test facilityAn ice encased train in the test facility (Image: Archant)

First Capital Connect will introduce the new first Class 700 Desiro City vehicles to the Great Northern Route in 2017.

But before they can safely ferry passengers builders Siemens put the vehicles through their paces.

A specialist climate chamber in Vienna, Austria, tested the locomotive’s ability to withstand extreme ambient temperatures, solar gain, ice, snow and wind.

Jonathan Bridgewood, First Capital Connect Thameslink Programme director, said: “Train reliability during very cold winter months can be a real issue for our passengers so we’re delighted to have witnessed the testing of the future Thameslink train to such extremes of temperature.

“These rigorous tests not only build our confidence in the reliability of the train but they also show that passengers will always be able to travel in comfort whether it is bitterly cold outside or a real summer scorcher.”

Before the trains run through WGC, Hatfield and Potters Bar they will be introduced to the Thameslink line in 2016.