Looks more likes cells forming under a microscope! I thought the vent photo was tough, but damn... okay I go for a Class 170 Scotrail.
It's not a class 59 or a scooby. There's a specle of colour in the top left corner which might be identifiable
It's not a 66, revealing more will give it away, I will add additional photograph in a sec Additional pic attached, same locomotive but different part of the LOCOMOTIVE