Sub-zero Bluebell

Not a funny story I'm afraid, but may be of interest to some! There is a video link to accompany the following:
http://uk.youtube.com/watch?v=D4sf5FSud00

As per usual, I reported to Horsted Keynes for P-Way duties bright and early last Sunday morning. According to someone’s car thermometer it was -8C, and the day didn’t get off to the best of starts when it was found that the hot water for the messroom had frozen (don’t ask!).

Our Wickham trolley wasn’t too happy at the cold either, and it took the best part of 45 minutes to get it ready to move. At least we took it in turns to lie on the sleepers underneath the vehicle to try and overcome the problem (the Loco boys may have to book on earlier, but at least they have a pit!). Eventually though, we were slipping and sliding our way out onto the “mainline”, adhesion being at a premium even on the level section outside Horsted signal-box.

The job was not a surprising one – checking West Hoathly tunnel for build up of ice (for those that don’t know, when they built the tunnel they “discovered” some underground springs. Hence the tunnel is permanently wet towards the north end – nice in the summer, but not so nice at this time of year!).

Anyhow, the main problem with this task was that we were at Horsted Keynes, and the tunnel was 2 miles away and uphill. But we were up for the challenge, and so with station limits safely behind us, the Wickham tried to pick up speed. Unfortunately the 1 in 63 gradient of Fireslip meant that it didn’t, but we carried on crawling up to Horsted House farm, where the change in gradient to 1 in 75 at least allowed a small increase in speed. The further easing to 1 in 134 at Black Hut allowed us to meet the 1 in 60 that leads up to the tunnel at line-speed.

Up to this point, there had been much comment as to how it was “rather cold” (some slightly stronger words may also have been used, but unfortunately I seem to have forgotten them). However, on entering the tunnel the drop in temperature was noticeable. It would have been interesting to have had a thermometer in there to see just how cold it actually was!

Suffice to say that the icicles (that we had cleared only three days previously) had built up again rather rapidly, as can be seen in the video. So it was on with the hard-hats and out with the poles, and about an hour later the worst of the ice had been removed. As the Wickham arrived back at Horsted Keynes to clear the way for No.9017 on the first “up” train of the day, there was time for a well deserved cup of tea before we set out in the cold once more for the next job of the day.

 

Those da*n icicles in the tunnel have always been a problem. First train through and the crew would cower, no that is not too strong a word, would cower up against the back plate just in case one came down a bit smartly. :smt013

I just hope that the crew on 73136 take it easy on the first train of the day when it is cold. :smt101

As for the tunnel being colder than the surrounding area, it is all down to the ghost. :smt051

 

The trouble starting the Wickham reminds me of trying to get a deisel to start (any would have done) on the W&L about 20 years ago. It was really cold - I don't know how cold, but the frost was like snow in depth. Any way we were supposed to use the loco in the shed (put there in anticipation of the cold), but the battery hadn't enough charge. Being a hunlset mines loco there was a starting handle. Now if your not familiar with the Hunslet 50hp mines loco, it has a very small cab (mines aren't all that big) and the starting handle is in the cab. The engine is a Gardner 4L2. 4 cylinder deisel about 8 litres displacement I think. It really needs a gorrilla to swing the handle, or two of you swinging in which case due to the cab size one of you must stand outside. As you can imagine even with a liberal dose of easi-start, we couldn't get it to go. We turned our attention to the loco parked in the platform adjacent to the road. This also had flat batteries and even de-compressing one of the banks of cylinders on the 6LXB engine couldn't get it going. At this point though a council gritting lorry came slowly past on the main road "he's got the same voltage system as us!" - so we flagged it down. Got them to park their lorry in the hedge (literally) between the platform and the road, and got out the jump leads. Only slight snag was that one of the leads was a couple of inches too short, and the lorry wasn't going to get any closer. No problem for the resourceful. Connect one end to the lorry, and the other end to something metal and then hold that to the battery terminal. "No no don't worry your wearing rubber soled shoes!!" The blue flash was quite impressive, but we got it started and no one was even slightly maimed

 

Easy Start - oh dear!

Once you get a diesel engine addicted to that stuff, you'll never get it to start without!

 

Biggest load of cods wallop ever to enter the world of mythology.

Loads of diesels throughout the world have OFFICIAL starting systems that use ether and ether based staring aids.

 

I don't want to make a big issue of this - life's too short! But I was a mechanic for over 20 years. That was my experience and that of every other mechanic I worked with.

I'll leave it there; this doesn't really follow the theme.

 

yeah i have experienced that aswell mechanic for 10 years

 

In the UK its probably more down to the fact that, once a diesel will not start in the UK winter temperatures, it is getting well sought into and Easy Start gives it the necessary push. However, it is generally well on its way to a top-end overhaul by this time and will probably only start on the stuff.

 

Steve's post has hit the nail on the head as to why diesels begin to fail to start and as to why the myth of engines becomeing addicted to ether is so widely believed.

You're right. Life is too short, especialy for me as I started way back in 1954 on hot bulb semi diesels and continued throughout my life with diesels includeing a personal fleet of 70 or so right up to the time I retired.

You have to ask yourself, "why won't this diesel start"?

No diesel will start until you raise the temperature within the combustion space to at least the ignition temperature of the fuel. In the case of 'pump diesel' this is around 725 degrees F or 385 degrees C.
To reach this temperature you have to compress the air to raise it's temperature to at least this figure. Not usually a problem if the engine is in good condition and it is generaly warm outside. However if the local air temperature is low and the engine has not been run for some time and is 'cold soaked', raising combustion temperature to the required amount will be a problem as the heat generated by compression will be 'leaked away' into the cold mass of the engine and insuficient heat will remain to ignite the fuel. This is observable in the large amounts of clag emitted by rail engines winter starting.

So how can we raise the compression temperature of 'cold soaked' engines.
1. We can raise the compression ratio by introducing oil into the cylinder, as per Lister lumps, or increase the fuel delivery volume as per engines with a 'cold start button' on the fuel pump.
2. We can spin the engine until such time as the constant heat leakage to the block has been overcome and sufficient heat has been left within the combustion space to fire the fuel.
3. We can raise the temperature of the air entering the engine.
4. We can introduce within the combustion space a substance that will ignite at a much lower temperature.

In the case of
1. Generaly this will be enough to start the engine but if not we can employ system 2 or 3 or 4.
2. Often this is the only way especialy with rail mounted engines. It can easily burn out the starter or damage the generator if this is the starting system. The batteries will of course have to be in top notch condition but will probably suffer buckled plates in the long run. Starting can be asisted by 3 or 4.
3. This is a system often used in depots where engines are started before drivers take over. A flare or 'burning candle' such as supplied by and recomended by Leyland for the 600/680 series of engines or indeed shoveing a burning newspaper down the air intake, a system widely used in the days of AEC engines in LT garages. Setting fire to the oil filled air filter has also been used before. The engineered alternative which does exactly this job is of course the glow plug heating system within the the intake manifold. A glow plug heating system built into the engine proper can be used to vaporise the fuel before we turn the engine over or to pre-heat the air within the combustion chamber.
4. Introduction of Diethyl Ether, 'starter fluid' which ignites at 360 degrees F/ 182 degrees C will enable a start to be obtained at roughly half the normal compression temperature and will supply enough heat to fire the diesel fuel. This is the system FITTED by Caterpillar, Detroit Diesel, Ryder Fleet Hire in the USA and Canada and recommended by John Deere and many others.

THE ONLY TIME STARTER FLUID SHOULD NOT BE USED IS WHEN HEATER GLOW PLUGS ARE OPERABLE.

So why has the myth of Easy Start come about. In most cases it is down to that first winter 'non start' because the cold weather has now shown up the wear that has gone un-noticed throughout the spring/summer/ autumn and now the crank speed is insufficient to raise the combustion temperature enough. A wiff of Easy Start overcomes the start problem and the wear gets steadily worse through the winter until it is so bad that the engine will not now start in normal air temperatures and will now only start if given a whif each time. In some cases it is down to the fact that the glow plugs have failed and this has not been noticed.

So in fact the myth of 'Easy Start Addiction' is down to a mis-diagnose of the engine condition.
Of course the myth will continue to be a passed on by word of mouth until someone produces an addicted engine in perfect mechanical condition that will not start unless wiffed with Easy Start.

If you have been interested enough to read this far you might like to know the chemical reason ether starts engines rather than the physical reason.

The application of compression heat to ether releases free radicals of peroxide which oxgenate the hydrocarbons within the diesel fuel.

As you say, not really on topic for West Hoathly tunnel icicles but something many on here have suffered I'm sure.

 

well I enjoyed the explanation. You are right the engine was knackered. In fairness it was 50yrs old and I doubt it had been apart in 30 of those. It also sufferred from being driven everywhere on full throttle and then being left I idle for long periods. i

 

The engine at least is historic. The design dates back to 1929! A 4L2 is 5.6 litres capacity, 1.4 litre per pot.

 

That's fascinating - thanks 2+2=5! I sometimes work with vintage buses and your explanation sheds light on a number of comments (and curses) I've heard in the depot!

John.

 

Can't beat a cold Gardner for lovely white clag!!!