Train Toilets

[modernrail]

Hi all,
There appears to be an acknowledged problem with toilets on trains. The tanks seem to be logistical difficult to empty (and I am sure there is quite a cost to the process) and also there appears to be a problem with tanks filling up and so toilets being locked out of use. I am not 100% sure of all the reasons for this - is it just the level of use they receive v the stabling/tank emptying opportunities during a typical day? The problem seems to be worse in the South East than the North, although TP Express regularly has toilets locked out.

In any case - I have been looking at a range of water saving technologies for other reasons and am looking in particular at a new toilet that works very well in highly used areas and will be going in to motorway service stations. I wonder whether this sort of technology might work well on trains to slow how fast the retention tanks fill up. It uses 1.5l per flush compared with a UK average of 9 litres, by taking in air. However, it is not a vacuum toilet as apparently they have a problem with interfacing with the sewerage system. How much water does a typical train toilet design use now?

 

[Bletchleyite]

Less than 1.5l, I think, from observation.

 

[daikilo]

Most modern aircraft use a vacuum system for toilets. They normally use about 0.6l per flush but I understand some are less than that. The advantage is that the effluent is drawn to a single tank system with a single servicing connection. Servicing of the tank is performed on the ground where there is no natural pressurisation of the system so I don't see why it should be an issue for trains.

That said, I doubt that a single servicing point would be feasible, even on fixed formation trains, due to the required flexibility of inter-car connections. Note that aircraft also have centralised fresh water storage and servicing.

 

[modernrail]

Most modern aircraft use a vacuum system for toilets. They normally use about 0.6l per flush but I understand some are less than that. The advantage is that the effluent is drawn to a single tank system with a single servicing connection. Servicing of the tank is performed on the ground where there is no natural pressurisation of the system so I don't see why it should be an issue for trains.

That said, I doubt that a single servicing point would be feasible, even on fixed formation trains, due to the required flexibility of inter-car connections. Note that aircraft also have centralised fresh water storage and servicing.

Are there problems with Vacuum toilets being used on trains? I understand that they are more prone to breakdown due to blockage? Is this the reason for all the silly announcements on Virgin Trains West Coast?

 

[Bletchleyite]

I think one thing that would help a lot (in terms of damage to flooring, mess for cleaners etc) would be if urine could naturally drain away into the tank even if the flush was not functional.

 

[AM9]

Less than 1.5l, I think, from observation.

Actually, I would think that the average flush is well below that. The The Water Supply (Water Fittings) Regulations 1999 mandated that no conventional WC fitted since then should use more than 6 litres in a single flush (and that the whole appliance should operate nornally with a single flush of that volume). Duo-flush systems also use 4 litres or less for 'smaller tasks' (sic).

 

[AM9]

I think one thing that would help a lot (in terms of damage to flooring, mess for cleaners etc) would be if urine could naturally drain away into the tank even if the flush was not functional.

That would mean that odour from the rest of the tank's contents could seep into the compartment.

 

[AM9]

Are there problems with Vacuum toilets being used on trains? I understand that they are more prone to breakdown due to blockage? Is this the reason for all the silly announcements on Virgin Trains West Coast?

Like many things on trains and on the railway in general, I suspect that users are less considerate than in the confined environment of an aircraft. For a start, anybody accessing an aircraft WC passes through a door that is visible to seated passengers. The user then returns to their seat via the same route and everybody is captive on the aircraft for the duration of the flight.

 

[modernrail]

Actually, I would think that the average flush is well below that. The The Water Supply (Water Fittings) Regulations 1999 mandated that no conventional WC fitted since then should use more than 6 litres in a single flush (and that the whole appliance should operate normally with a single flush of that volume). Duo-flush systems also use 4 litres or less for 'smaller tasks' (sic).

I am probably being thick, but does that not mean the average flush on non-train toilets is well above 1.5l? In the range of 4l to 6l for a newer toilet (with duo flush) and possibly above 6l for older toilets, of which there are plenty around. I have always presumed vacuum and non-vacuum train toilets use less that normal building based toilets.

 

[Bletchleyite]

That would mean that odour from the rest of the tank's contents could seep into the compartment.

The U-bend is hardly a new piece of technology and would avoid that.