Why is it that some trains come flying into the station, and some come in painfully slow? Is it due to newer drivers being trained differently to older BR trained drivers? Rail conditions?
Please watch these two videos the first one shows a nice fast approach and the other shows a much slower one:-
-Approach begins at 25:18
-Approach begins at 48:54
As you can see there is big difference!
I'd concur with the other responses which suggest that it's largely down to the individual.
There's a range of factors which might demand a more cautious approach - poor railhead conditions, red signal on the end of the platform, tighter stopping berth with less margin for error, train with dodgy brakes, someone acting strangely on the platform (etc etc), however when none of these conditions apply and all other factors remain the same there *is* still considerable variation from person to person. Simple reality is some people are more comfortable than others at hammering in at 40 mph on full or nearly-full brakes. As long as there isn't an issue with slower people losing time, or faster people having overruns, there shouldn't be a problem with this.
I'd also add that that there may well be a bias towards more long-in-the-tooth drivers coming in faster as that was much more established practice in the distant past, but a lot will also depend on who trained someone.
London Underground has quite a variation too - indeed this is one of the reasons for ATO as it's an inconsistency which ATO removes. On LU you'll find considerable variation between people with some reluctant to "hit" a platform at more than 25 mph whilst others are quite happy to do same at 35 mph. On lines with longer trains (e.g. Central, Jubilee, Victoria, Metropolitan) 40 mph is quite possible in good conditions. From personal experience I'd suggest there's little correlation between faster drivers and having more incidents. It used to be in the Rule Book that drivers should enter a platform as fast as possible, but this has drifted away in favour of defensive driving over time. Again, older hands *tend* to drive more aggressively, but as always there's exceptions. Some types of LU train in the past more or less required the driver to throw everything in and gradually release as necessary, whereas nowadays the opposite is generally taught, again old hands are more likely to drive in the first of those fashions. It's generally poor practice to be fully releasing brakes halfway down a platform - again on some types of LU train this can be inviting an overrun.
One final thing, there's also considerable variation between how drivers make their final stop. Good practice is to come to a stand on minimum or no brakes to produce a completely imperceptible stop. Again some drivers are better at this than others. Someone stopping with too much of a jolt should be being flagged up on assessments if being picky.