With FROM RUSSIA WITH LOVE the series was still at the start and already had had to deal with some troubles, having to drop Thunderball in favour of Dr No just one of them. At one point, Len Deighton had been working on a script for Eon and the task was somewhat tricky since Bond only enters after the first third. The series hadn’t yet found its balance; they knew what they wanted, but not yet how to get there.
The idea was to translate a somewhat stuffy character with little humour onto the screen - actually transform him to what Fleming later called “stage Bond” - with sex appeal and luxury and all the exotic detail the ordinary joe dreams of when thinking about the lush life of the rich.
But they also wanted to keep that bizarre element of the books, the fantastic things that make us shiver, glad to be just watching instead of taking part. And all that in a handy package they can get past the censors and allows a huge audience to have a thrilling ride.
The pre-titles were inspired by Alain Resnais’ Last Year at Marienbad, where a similar park (actually Schloss Nymphenburg, Munich) is important for the dreamlike surreal atmosphere of that film. The idea to let a killer train on a Bond double is strange - why would the double wear that mask at all? and what if he had killed Grant, would they then have sent him? - and I think I’ve read somewhere it was indeed questioned whether that wouldn’t put off the audience or if they’d understand that part at all. If memory serves the decision was even to show the double under the mask with a moustache to make it clear this wasn’t the real James Bond who has just arrived at the end of his usefulness.
Personally, I would perhaps have wanted to set the final battle between Grant and Bond once more in that park because of that beautiful atmosphere. But the train fight is evidently a classic in its own right and an early highlight that wasn’t surpassed for some time.