The photograph is exactly as-taken from the secondman's position!
The road bridge is Succombs Hill (Woldingham) and parts of it are at 1 in 4 as it drops down the valley side from Warlingham to Caterham.
The railway is descending down (along the side of the Caterham Valley) from Oxted tunnel toward Croydon; roughly at 1 in 100 at this point. The diesel unit (a 171 formation) was travelling around 70mph on this descent.
@RAF96 - I couldn't possibly disagree with your sentiments.