I went looking for the scene containing this still: 

I didn't find it, but what did come up when I searched 'The Railway Man emotional scene' was this sweet moment between the two men in which Sanada's character, an ex-officer in the Imperial Japanese forces, breaks down and is comforted by Firth, who he (I think) had previously treated horribly.
https://www.youtube.com/watch?v=z6TfmoDYy2s