There is a dark, deadly theme in this poem. The send-off is not a happy occasion. There is no celebration, no ceremony in this send-off – maybe because it happens so often, maybe because the people of the town have no relationships with these soldiers from other places: “They were not ours” is quite an isolated line and shows this lack of connection, whilst the mystery and secrecy of the whole business is emphasised in “We never heard to which front these were sent”. There is a sense of secrecy, of a hush-up, of a conspiracy that we are drawn in. “We never hear”. They go into their camps in France, anonymous fighters from all over the country, heading towards a dark future that will bring them back changed (if it brings them back at all).
The poet uses personification to create quite a sinister effect: “Then, unmoved, the signals nodded, and a lamp/Winked to the guard” – it makes it sound as though all the workings of the railway station are in some kind of conspiracy and in on some secret then the men are unaware of. The winking of the lamp could also refer to flickering light – which could be symbolic of flickering (dying) life?