Could train toilets dumping onto track return in a "friendly" way?

[brad465]

A colleague of mine, now working in a different part of the country in waste management, revealed that they have been collaborating with a TOC in this country looking at getting permission to allow toilet waste to be dumped on the track, after having been through a bioreactor toilet. Despite the work of such a device, they are sceptical about it. Doing some research it appears to be something a few operators have trialled or are set to do so, so thought I'd ask if this practice will return more widely, and would the public accept it?

Here's an article about Scotrail trialling it on Class 334s, with link from 2021 on it also suggesting Southeastern might modify class 375s to do this as well (although not specifying if they'll be released onto the track in the process).

Train toilet bioreactor on test

UK: What supplier Protec says is the first bioreactor train toilet in the UK is being tested in service on a Class 334 electric multiple-unit which ScotRail leases from Eversholt Rail. The bioreactor uses bacteria to break down waste while the train is running, with a heater sterilising the...

www.railwaygazette.com

UK: What supplier Protec says is the first bioreactor train toilet in the UK is being tested in service on a Class 334 electric multiple-unit which ScotRail leases from Eversholt Rail.
The bioreactor uses bacteria to break down waste while the train is running, with a heater sterilising the waste water which can then be harmlessly discharged to the track.
Protec said this offers the opportunity to empty the tank every two months rather than daily, meaning less downtime for the trains and increased availability of toilet facilities for passengers.


‘The availability of on-board facilities forms an important part of the overall customer experience and any efforts to improve in service reliability is welcome’, said George Davidson, Transport Scotland’s Rolling Stock Programmes Sponsor.
Similar bioreactors are already in use Switzerland and the Netherlands.
‘We are delighted to provide one of our Class 334 trains and fund the trials to enable Protec to prove the benefits of the Bioreactor to the UK rail industry’, said Kevin Limb, Chief Engineer at Eversholt Rail. ‘We look forward to receiving the results of the trial next year.’

 

[yorksrob]

South Eastern could do with this technology. Emptying toilet tanks seems to be a blind spot of theirs.

 

[fgwrich]

Isn't this in effect what the 701s are supposed to do?

 

[D365]

South Eastern could do with this technology. Emptying toilet tanks seems to be a blind spot of theirs.

It’s a good job that the 375s are being looked at, then!

 

[Nym]

Then they'll simply be failing to fill them instead.

One should note by the way, these things need a lot of power, so retrofitting them to something with alternators not designed for heavy loads or lacking large enough converters, nah, won't happen without a lot of work.

 

[D365]

One should note by the way, these things need a lot of power, so retrofitting them to something with alternators not designed for heavy loads or lacking large enough converters, nah, won't happen without a lot of work.

Would this not form part of the costing exercise?

 

[SargeNpton]

Doubt that those who work on the tracks would be amenable to this.

 

[skyhigh]

Doubt that those who work on the tracks would be amenable to this.

The whole idea is it's only sterile treated water that would be discharged - a world away from the old discharge toilets.

Then they'll simply be failing to fill them instead.

This is the issue. With the stock I sign, the waste tanks are generally sized so that they last the same range as the fuel tanks - the fresh water tanks in comparison are much smaller and will last a day or so. That's generally okay as stabling points including main stations have fill points but the majority of toilet faults are either caused by misuse/blockages or empty fresh water tanks. It's very rare for the waste tank to be full.

There is also the fairly common issue with 19x that the water tank heaters are defective (or simply off when the unit is shutdown overnight) meaning the unit dumps the fresh water in cold temps to prevent frost damage. The PRM bogs on 15x do a similar thing but to a lesser extent.

 

[Nym]

Would this not form part of the costing exercise?

Remember that decisions are made by optimists who like shiny things and ignore assumptions.

 

[dm1]

SBB (along with numerous other European operators) have them fitted to their more modern train fleets (e.g. the FVD units) They work fine, but do have some quirks. The treated wastewater is collected in a tank until it is full, after which it must be heated up to sterilise it, before it is released onto the tracks. However, the tank for this is quite small, so these releases have to occur fairly frequently, otherwise the toilet becomes out of service before one occurs.

The release can only occur in a fairly narrow speed range, between about 5 and 40 km/h, to avoid corrosion damage from spray to the car bodies of the trains. It is also GPS-controlled to limit where the release can occur, as although the wastewater is sterile, it is still quite pungent. With some service patterns, the time spent in the required speed range can be very small (especially long-distance services with few stops and lots of high-speed running), so SBB found themselves having to allow the wastewater relase at every opportunity, even where they would prefer not to - including in the underground platforms at Zürich HB, which even led to them needing to put posters up apologising for the pungent smell at the height of summer.

The bacteria in the bioreactors can also be overwhelmed if the toilets are used to much and they are not sized correctly, which also causes odour issues and may lead to toilets becoming temporarily out of service.

These are all solvable problems from a technical perspective, but are factors that do not need to be considered when using simple containment tanks. The advantage is that they only need to be emptied every few months rather than every few days.

 

[yorksrob]

What is the residual mass like which has to be emptied every couple of months ?

I'm imagining it to be similar to peat.

 

[H&I]

The whole idea is it's only sterile treated water that would be discharged - a world away from the old discharge toilets.

Since the water has been sterilised, perhaps the water could be re-used as grey water which would extend the range of fresh water tanks.

 

[Trainbike46]

SBB (along with numerous other European operators) have them fitted to their more modern train fleets (e.g. the FVD units) They work fine, but do have some quirks. The treated wastewater is collected in a tank until it is full, after which it must be heated up to sterilise it, before it is released onto the tracks. However, the tank for this is quite small, so these releases have to occur fairly frequently, otherwise the toilet becomes out of service before one occurs.

The release can only occur in a fairly narrow speed range, between about 5 and 40 km/h, to avoid corrosion damage from spray to the car bodies of the trains. It is also GPS-controlled to limit where the release can occur, as although the wastewater is sterile, it is still quite pungent. With some service patterns, the time spent in the required speed range can be very small (especially long-distance services with few stops and lots of high-speed running), so SBB found themselves having to allow the wastewater relase at every opportunity, even where they would prefer not to - including in the underground platforms at Zürich HB, which even led to them needing to put posters up apologising for the pungent smell at the height of summer.

The bacteria in the bioreactors can also be overwhelmed if the toilets are used to much and they are not sized correctly, which also causes odour issues and may lead to toilets becoming temporarily out of service.

These are all solvable problems from a technical perspective, but are factors that do not need to be considered when using simple containment tanks. The advantage is that they only need to be emptied every few months rather than every few days.

The key point here is that many European operators use them, so technically there doesn't appear to be any issue with these systems. I know NS uses them as well, and the toilets tend to not have issues too often

 

[zwk500]

so thought I'd ask if this practice will return more widely,

I think it is unlikely, although some routes could be seen as suitable for it. However this wastewater would at least avoid the problem of dumped waste clogging the ballast.

and would the public accept it?

The public wouldn't care one jot, so long as they can use the toilets on the train as and when they need to.

 

[NoRoute]

I am surprised, I would have assumed the residence time required to break down the waste would result in quite a large tank being necessary. Coupled with the requirement for the train operator to then monitor and maintain the biological conditions necessary for effective digestion of the waste, seems like it could be problematic, with a lot of scope for things to go wrong if waste needs to be discharged prematurely, or if the process goes wrong and it turns septic/foul.

I would have thought the operators would instead focus on quicker and easier ways to empty the tanks, leaving the sewage processing to the sewage works, rather than trying to integrate a mini-sewage works into the train.

 

[Towers]

SBB (along with numerous other European operators) have them fitted to their more modern train fleets (e.g. the FVD units) They work fine, but do have some quirks. The treated wastewater is collected in a tank until it is full, after which it must be heated up to sterilise it, before it is released onto the tracks. However, the tank for this is quite small, so these releases have to occur fairly frequently, otherwise the toilet becomes out of service before one occurs.

The release can only occur in a fairly narrow speed range, between about 5 and 40 km/h, to avoid corrosion damage from spray to the car bodies of the trains. It is also GPS-controlled to limit where the release can occur, as although the wastewater is sterile, it is still quite pungent. With some service patterns, the time spent in the required speed range can be very small (especially long-distance services with few stops and lots of high-speed running), so SBB found themselves having to allow the wastewater relase at every opportunity, even where they would prefer not to - including in the underground platforms at Zürich HB, which even led to them needing to put posters up apologising for the pungent smell at the height of summer.

The bacteria in the bioreactors can also be overwhelmed if the toilets are used to much and they are not sized correctly, which also causes odour issues and may lead to toilets becoming temporarily out of service.

These are all solvable problems from a technical perspective, but are factors that do not need to be considered when using simple containment tanks. The advantage is that they only need to be emptied every few months rather than every few days.

Well they sound like great fun!

 

[Turtle]

So, all in all, it's probably a no.

 

[Trainbike46]

So, all in all, it's probably a no.

Given the number of operators on the mainland that use them, and that according to the SWR website the 701s are fitted with them, you appear mistaken

Fully accessible bioreactor Controlled Emission Toilets (CET), including for those using wheelchairs, will be available across the entire fleet. These types of toilets are the first to be rolled out on an entire UK fleet and are used in Europe, including the Netherlands and Switzerland.


CET toilets biologically and thermally treat waste to produce wastewater which is compliant with EU bathing water standards. Once the trains are introduced, there will be 1 toilet per every 5-car train and 2 per every 10-car train.

source: https://www.southwesternrailway.com/travelling-with-us/our-trains/arterio

 

[AY1975]

Is it OK to flush this type of toilet when the train is stood at a station?

 

[skyhigh]

Is it OK to flush this type of toilet when the train is stood at a station?

Yes.

 

[Tony_Foster]

Having been lineside when an HST dumped its toilet, I strongly oppose this, having anything dumped in your face is unacceptable. There isn't anywhere to wash your face even!
We were taught to turn away to avoid ballast and faeces when trains pass but the wind was strong!
I was a contractor, now retired, to Network Rail designing the GW OLE and sometimes had to go on site, rarely a pleasant experience (imagine down the Severn Tunnel) but some have to do it every day.

 

[yorksrob]

According to this months Modern Railways, SWR's new 701 fleet already has them !

 

[D365]

Isn't this in effect what the 701s are supposed to do?

According to this months Modern Railways, SWR's new 701 fleet already has them !

Yes, and it's been discussed in the Class 701 discussion.

 

[yorksrob]

Yes, and it's been discussed in the Class 701 discussion.

Ah thanks