For once, a new way of rail-head cleaning

[whole diary]

[stuving]

You'd be forgiven a degree of scepticism about any new way of getting leaves and their slippery residues off rails - we keep getting "the end of this problem is nigh" news releases followed by not a lot. This one is at least a novel idea - while it's been in development since 2015, I don't recall hearing about it before. But it's by no means obvious why it should work better than other methods.

From Sheffield University:

•    University of Sheffield engineers have developed a new track cleaning system to remove leaves from railway lines - an issue which costs the rail industry millions of pounds each year
•    Pioneering technology can be deployed onboard passenger trains - the first time passenger trains have been used to clean the line anywhere in the world
•    Trials have shown the cleaning system reduces delays, improves braking distances and is significantly more effective at removing leaves from the line than the current track cleaning methods
  

Delays to train services caused by leaves on the line could finally become a thing of the past, thanks to new track cleaning technology developed by engineers at the University of Sheffield.

The new rail cleaning technique, developed by a team of researchers led by Professor Roger Lewis from the University’s Department of Mechanical Engineering, uses dry ice pellets in a stream of high pressure air which freeze the leaves and then as the pellets turn back to gas they are blasted away from the railhead. ...

I'm not so sure about this statement: "The system is also much better for the environment as it uses reclaimed carbon dioxide." Rather than what?

[infoman]

radio bristol had an interview with Prof. roger Lewis on monday 4 october about the new cleaning method starts approx 17:30pm

[broadgage]

I thought that there was a shortage of carbon dioxide ?

[ellendune]

I thought that there was a shortage of carbon dioxide ?

Also I thought we were trying to reduce Carbon Dioxide emissions?

[PrestburyRoad]

I thought that there was a shortage of carbon dioxide ?

I believe the shortage is food-grade carbon dioxide.  So the gas may still be readily available in less-pure form - and this might well be suitable for rail-head use.

[stuving]

I'm not so sure about this statement: "The system is also much better for the environment as it uses reclaimed carbon dioxide." Rather than what?

That was not just unclear, it was misleading. I'm sure they were saying they didn't use the CO₂ from fertilizer plants, which use methane as a feedstock (and has recently been in short supply). CO₂ could be called "recycled" if it comes from the atmosphere (from oxygen and nitrogen production) or captured from fermentation, for example. What I think is specious is the suggestion that this machine is uniquely capable of using such dry ice. It can hardly be rather than other dry-ice-based rail cleaners, surely?

[broadgage]

I thought that there was a shortage of carbon dioxide ?

I believe the shortage is food-grade carbon dioxide.  So the gas may still be readily available in less-pure form - and this might well be suitable for rail-head use.

So far as I am aware, "dry ice" or solid carbon dioxide comes in only one grade, it is either dry ice or it is not.

Carbon dioxide in cylinders is allegedly available in food grade and in not food grade. I doubt that there is any difference. I have observed both types of carbon dioxide cylinder being filled from the same bulk tank and in similar surroundings.
The workers handling the food grade cylinders wore white coats whereas those handling the industrial cylinders wore blue overall coats, perhaps that is the difference!

Most but not all industrial carbon dioxide cylinders have an internal dip tube such that LIQUID and not vapour emerges when the valve is opened. Often used to freeze water pipes for repairs. The presence of this internal dip tube is indicated by an external white line along the length of the cylinder.

[stuving]

While we are still looking for that elusive solution to the adhesion problem, which still causes accidents and wheel flats, over on Long Island it's already been found! And I've heard they have a leaf or two in those parts. This is from MTA LIRR:

LIRR’s Leaf-Fighting Technology Gets Stronger and Faster

Long Island Rail Road
Updated October 30, 2020 10:15 p.m.

The Rail Road Adds Second Laser Train and Increases Speed Resulting in Less Delays and Trains Being Taken out of Service

MTA Long Island Rail Road (LIRR) today announced that its industry-leading laser train is working even faster and harder to battle the danger of fallen leaves on the tracks. The LIRR has added another laser train and increased the speed to 25 mph, up from 15 mph, covering more of the system and minimizing the number cars from being taken out of service during the fall season...

Since 2018, the LIRR Maintenance of Equipment Department (MoE) has transformed how to tackle the negative effects of leaf fall season with innovative solutions such as partnering with Amsterdam-based manufacturer Laser Precision Solutions who pioneered the technology. The laser train works by using high-intensity lasers to remove contaminated layers from railway tracks, requiring only one pass to leave a smooth, clean rail behind. With the addition of a second train, all vital parts of the network can be cleaned every 24 hours. With an effect lasting at least 24 hours, this means that slip-slide will be minimized to a very low level.

Note that that was a second train being added in autumn 2020, after running the first one as a trial for two years.

The system is quite small, only 700 miles of track, so doing all that at 25 mph would take 14 hours by two trains. Most of that track is in the less-busy outer branches, so the slow RHTTs^▸ (Rail Head Treatment Train) should not be a serious obstruction.

While deploying the equipment over the whole GBR^▸ (Great British Railways) network might not make sense (yet), the London commuter part at least can't be so different.