Best Thrash of the English Electric Class 37 Diesel Locomotive

[@jonathan461965]

Looks like sparks under the third picture at 2.30 into the video?

[@GJ37425]

It's a Network Rail 'test train', it's a light used to help monitor track & ballast condition

[@crazyfroggie6546]

What was the cargo of the first train, seems odd having 2 locos on a 5 wagon train