It does seem now that there is almost too little emphasis in certain quarters on the competency of a driver to maintain a reasonable speed between stations. I'm aware of several incidents in the last few months of trains losing 1 or 2 minutes and thereby causing ridiculous knock-on delays when they hit a busy part of the network, and when investigated, there is no real reason (signals, weather, speed restrictions, wheelslip/slide, etc.) to have had the delay. At the extreme end, I recall being on a train from East Grinstead a few years ago which lost in the region of 20 minutes (on a sub-60 minute journey) for no definable reason other than slow driving. I politely asked the driver on arrival, they looked at their watch - and went "oh *!?*, sorry mate, no idea how that happened..." - and I think that was entirely genuine! Weirdly, these are probably the same drivers who, when on a very slack schedule on a late-night DOO service, don't look at their watches and leave everywhere early...
I am well aware that rushing and trying to beat the clock can cause operational incidents, and I am also aware of the implications a train running overspeed can have on the safety of the line - and a driver's career. And I've been on a number of trains that have come to a screeching halt with a TPWS activation, with the subsequent responsibility of trying to work out how to tell all the passengers why they're running late, in a world where the very phrase "operational incident" simply no longer works very well. But the efficiency of certain drivers is certainly open to challenge.
Luckily, an equal or greater number of drivers are very good at clawing back a few seconds here and there. So long as they don't put anyone at risk, I don't mind - quite the opposite. Even if it's only 15 seconds between each station, it can let you cross the next major junction in the right order, or allow someone to make a cross-platform connection, and that's worth its weight in gold.
And as for the slow drivers, there are a few things which are done. There are Driver Advisory Systems (DAS) being installed, or already present, on many trains. The accuracy and usefulness of these vary, but what many do have is the ability to display a schedule and how the driver is progressing against it. Just the difference of the schedule card being illuminated in an official position amongst all the other controls could be what is needed, rather than being stuck on the cab noticeboard, up to one side beside the window (as it is on many multiple units). And with the increase in focus on non-technical skills, crew of all descriptions may be able to work out how they can work more efficiently with each other and with the processes in place, without having to feel like a machine.