Thanks for that DStock7080
De-icing equipment is on 30% of the fleet. I guess that means the S8 stock?
It is fitted to a number of trains assinged to each line, so is fitted to S7 and S8 stock, indeed the S7+1 units in use on the met to cover the shortage of S8s are S7s with a de-icer car inserted into it. This can be spotted on S Stock as the car is numbered in the 25xxx series rather than 23xxx (it is fitted to the M2 car) and has a blue circle by the car number, and a white circle by the train number on the cab ends.
Sleet brushes are only on the contact rail, which I presume is the one that provides power to the train? Do you have these Sleet brushes on both positive and negative rails.
Indeed it is the one that provides power via the shoegear, and yes, the sleet brushes are fitted on the posi and negi rail contacts (all three positions).
The DeIcing fluid and the sand. Are they used together in any way?
Does anyone have any photos of these devices please?
In terms of Sand and De-icer, they are used for different things, but is can be possible to need the use of both of them.
The sand is used in areas of poor traction, where leaf fall or other contaminants have reduced the adhesion on the running rails, sand is used to improve the 'grip' between the wheels and running rails.
De-Icer is used to remove a film of ice that tends to build up on top contact 3rd and 4th rail systems, the sleet brushes then remove the sleet that remains on the rail head to give a good contact between the shoegear and rail head of the conductor rail.
Problems come when there is a total ice layer built up, no amount of de-icer or brushes can remove, this then needs to be removed by hand with ice scrapers, or with a de icer unit that does not need to take power from the conductor rails.
In practice, the last sets of shoegear at a minimum are able to maintain contact with the conductor rail, but on older stocks (and new stocks with silly battery charger methods like S Stock and 09TS) if you run in one direction for too long with no juice on the front end in high iced conditions, you will end up loosing the control supply on the leading end and have a dead cab. (I beleive a couple of mods have solved this issue on S7s and the rebuild work on the 09TS, the 92TS, 95TS and 96TS never suffered this problem).
The D78 Stock has had a problem for a while that it is very hard to distinguish when to place de-icer with the way the detection circuits are set up, this was addressed on the 73TS (very similar electrical design) by changing to a more modern detection system, similar to that fitted to the S Stock from new.
