"The Loos Empty Out Where!?"

Some people are surprised by this, that yes, our loos still empty out onto the track. Inevitably the follow up is then "Why don't you fit retention tanks?" This question comes up on a fairly regular basis, both with my C+W and TTI hats on. Richard Johnson, formerly our Head of Department for nearly 20 years, now our director and chairman, thought it would be a good topic for a blog post, so next time someone asks, we can point them here! Over to Richard:

I thought that I would send this, as I have been involved in some respects in plans to fit controlled emission tanks (CET) on some Mk 1 & Mk 2 coaches which are used on the national network. It is not as easy as it sounds. I have seen a comment or two that we should fit them on the GWR. If it was easy, we would have done so long ago.

The issues:

• Our toilets discharge a great deal of water each time the toilet is flushed. All this water and waste would need to be captured, so the capture tank would need to be at least as big as the current overhead water tanks are. You have seen how big they are. There is no room for such a tank over the bogies, so it would have to fit elsewhere underneath. That would involve complex plumbing and large diameter pipes if we rely on gravity feed.
• The weight of water in the overhead tanks would be transferred to underneath the coach. A gallon of water weighs ten pounds. That would alter the weight distribution of the coach, and could require bogie spring settings to be adjusted to compensate. Our coaches are not designed to carry that amount of weight underneath the solebar.
• Once the capture tanks were full, they would have to be emptied before the overhead tanks could be filled, or we would get overflowing toilets in the train. How would we know when the capture tanks were full without gauges for the guard and TTi to keep an eye on before they lock a toilet out of use?
• On modern trains, there is a vacuum or electric system which sucks the water and waste into a capture tank. You will recall that it is a small amount of blue sterilised  water, not the vast amount which we get when we flush. That allows the capture tank to accommodate much more and remain serviceable for much longer.
• We could replace all our train toilets with a modern stainless steel vacuum or electrically operated system. How much would that cost, and how would it all be powered? Modern systems are upwards of £20k each unfitted. They need a dedicated power source.
• Finally, how would each of the capture tanks be emptied? We could have a complex plumbing system built alongside where the train is parked, so that each tank could be connected to a hose which drained into our site sewerage system. That would overwhelm our current septic tanks at Toddington in a short time, and would be costly to keep pumped out regularly. Whose job would it be to connect that up every night? A trainee TTI perhaps!
• Alternatively, we could fit  some sort of connection to the capture tank, so that a commercial septic tank emptying tanker could connect to each one in turn and pump it out. That would require the tanker to be able to access a road alongside the parked coaches, or for a lengthy hose from each coach to the tanker whilst they are parked at Toddington. How much would that road tanker cost each day, and where would we park the coaches to do it. Would it be the guard or TTI who stayed behind after services to supervise all this and any necessary shunting? It would be a long process to empty eight coaches like this.
• If we were operating more than one train, it would mean evening shunting of the rakes so that each train could be emptied ready for the next day.
• If for any reason the tanks were not emptied at the end of the day, it would potentially put all toilets out of use the next day until they could be emptied. There would need to be a handover system so that a new train crew each day knew that the tanks had been emptied previously.

So, as you can see it is not straightforward. We have looked at it in detail in the past. We have a licence from the Environment Department which specifically permits us to discharge waste onto the track, so we are not in breach of any law in doing so.

Many thanks to Richard for sending that in. So there you go, it really is jolly difficult!