I do think that, whilst there have always been certian known low adhesion spots under certian conditions, the epidemic levels reached during the 1990s were very much a product of the modern railway.
Back in the early days of H.S.T. operation I recall a discussion which took place over poor adhesion on the power cars largely put down to disc braking where, in the absence of tread brakes, there was nothing to scrub and condition the wheels leading to both a build up of crud on the one hand and a more polished surface on the other.
A further point was raised later during the "Wrong kind of snow/leaves on the line" era when it was decided to do something about the actual rail conditions, hence "Sandite" etc. but what was mentioned about this was, like the brake block/wheel surface issue above, the idea that modern bogie design was also related to the phenomenon. As hunting (yaw) is now largely damped out there is limitation of the tendency of the wheelset to oscilate from side to side and it was this movement which assisted in the conditioning of the rail surface.
Hunting cleaned the rails and blocks cleaned the wheels it would seem. I would have thought that the lineside environment would have become ever more important because of this but the reverse appears to be the case. I did also think that sanding gear for D.M.U.s would have been a good idea but, at the time, there was talk of a "One shot only" type canister for poor adhesion problems although this would have been no good if needed more than once between depot visits. Ultimately, it seems that some D.M.U.s have been provided with sanding equipment although it was thought of many years ago; I once saw some drawings of the original Derby Lightweight Units whose bogies were shown with sanding gear!
Disc braking and smooth riding bogies are, of course, here for the duration so I would suggest that a well tended lineside coupled with universal sanding provision and a more limited rail head treatment programme in the true blackspots might just finally bottom the problem.
Then somebody mentions cost, the meeting is adjourned until April and so ad infinitum.
