Blue streak

I like better the B/W version. This composition does not need colours, in my opinion.

Sorry Gábor but I really think I prefer this one. It helps to answer Nezih's question.

I prefer the colour version, looking at the B&W the large dark area of cab and the bright number seems a bit overpowering when compared to the colour. Probably intentional but if so I feel the image would have been better if the rest of the engine had been leaving the frame on the right.
I think what Judges say about reading left to right really applies here.

So colour gets my thumbs up.

PS; is that hole under the brass plate where they stick the key to wind it up

Well, it really does, Paul! However, although I like this too, I still prefer the mono, like Gabor, as it is more impressive. Digits look much, much better in black & white with shades of gray than yellow and red.
You see opinions differ; Alan thinks the opposite about the number,but I like its bright white matching the clouds to create a balance. Is it important? I don't know. I tend to think so.

They lost the key that's why Mallard doesn't run any more. Its now a museum exhibit.
David

I like this colour version. Nice shot. i think the clouds add a lot to this picture.
Well done,
Regards