Engines needing to be pre-heated

ryan125hst · 17 Jul 2020

How many train engines require some sort of pre-heating consideration before starting? I have seen videos of old locos cold starting and taking a while to get going, throwing out loads of clag in the process! I've also seen videos of Sprinters, Turbostars etc. being left in a platform shutdown and then seemingly restarted without an issue. However, I seem recall that the MTU engines in HST's need to be kept warm from the Electric Train Supply from the other power car (when shut down at a terminus station) or from a Shore Supply. I'm not sure what the consequence of not doing this are, but I'd imagine it'd reduce the number of hours between overhauls if this wasn't done?

It came to mind whether the Hitachi AT300's of all TOC's could be shut down and then restarted after an hour, or a few hours, or whether an engine would need to be left on or a short supply be plugged in to prevent problems?

RailUK Forums

irish_rail · 17 Jul 2020

HsT MTUs need to be at 40degrees to start, and for 80x they should be at 45 degrees.

ryan125hst · 17 Jul 2020

Is there a way in which this can be achieved without another engine running or a shore supply? I'm assuming not as it'd take a large amount of energy to achieve that and I can't imagine the battery would be able to supply it.

How long following shutdown would the engine temperature drop below these temperatures?

CyrusWuff · 17 Jul 2020

165s (and presumably 166s) certainly have a pre-heater that automatically kicks in at low temperatures.

I've seen a 165 vehicle pretty much engulfed in smoke on a particularly "enthusiastic" unit, and the resulting panic that ensued from someone who was seeing it for the first time.

Richard Scott · 17 Jul 2020

Any Maybach engine I believe. Seems to be a German thing. Used to see diesels plugged in all over the place in Germany.

gimmea50anyday · 17 Jul 2020

802s have an engine preheat system. This is activated by the driver approximately 10 minutes before changeover to diesel power. I would imagine all the IET derived units have the same function.

Richard Scott · 17 Jul 2020

Do all MTU engines need preheating or do the smaller ones not require it such as those fitted to 170s etc?

hwl · 17 Jul 2020

Richard Scott said:
Do all MTU engines need preheating or do the smaller ones not require it such as those fitted to 170s etc?

The smaller ones are effectively Mercedes engines with an MTU badge on it, not proper MTU engine...

Richard Scott · 18 Jul 2020

hwl said:
The smaller ones are effectively Mercedes engines with an MTU badge on it, not proper MTU engine...

As a digression did the Merc engined V200s need preheating? Thought MTU was an amalgamation of MB and Maybach anyway and perhaps preheating was a requirement of Maybach engines that spilled over when MTU was formed?

gimmea50anyday · 18 Jul 2020

The whole point of engine preheating as I understand is to minimise emissions. Cold engines don’t fully burn the fuel hence why you get the very smoky exhausts when the likes of a 37 or 47 starts and given the size of the engines they take a while to get up to operating temperature. Most diesel cars have glow plugs fitted which helps warm the engine cylinders before the car is started, hence why you allow the coil light to go out before turning the key. It’s effectively the same principle but on a larger scale. Very occasionally if preheating hasn’t been done properly an 802 will produce some white exhaust when leaving York (or Durham) but this usually disappears after around 10-15 seconds.

Richard Scott · 18 Jul 2020

gimmea50anyday said:
The whole point of engine preheating as I understand is to minimise emissions. Cold engines don’t fully burn the fuel hence why you get the very smoky exhausts when the likes of a 37 or 47 starts and given the size of the engines they take a while to get up to operating temperature. Most diesel cars have glow plugs fitted which helps warm the engine cylinders before the car is started, hence why you allow the coil light to go out before turning the key. It’s effectively the same principle but on a larger scale. Very occasionally if preheating hasn’t been done properly an 802 will produce some white exhaust when leaving York (or Durham) but this usually disappears after around 10-15 seconds.

I thought initially it was to reduce engine wear as a warm engine's tolerances are closer to what they should be at normal operating temperature?

CW2 · 18 Jul 2020

Richard Scott said:
As a digression did the Merc engined V200s need preheating? Thought MTU was an amalgamation of MB and Maybach anyway and perhaps preheating was a requirement of Maybach engines that spilled over when MTU was formed?

I'm pretty sure the V200s did need preheating. I have a vague idea that the train heating boiler may have been involved in this.

gimmea50anyday · 18 Jul 2020

Richard Scott said:
I thought initially it was to reduce engine wear as a warm engine's tolerances are closer to what they should be at normal operating temperature?

You could well be right, this will no doubt be an added benefit too.

Bletchleyite · 18 Jul 2020

Many if not all diesel cars have a pre-heat, though of course with the much smaller engine it's fine to just power the glow plugs from the battery. On older cars like the diesel Series Land Rover I once had it was its own key position that you had to engage and leave there for 10-15 seconds (with a dashboard yellow light showing) before turning the rest of the way to start. Turning all the way too early would result in a sudden pea-souper as half the fuel tank just went straight out of the exhaust unburnt.

hwl · 18 Jul 2020

Richard Scott said:
I thought initially it was to reduce engine wear as a warm engine's tolerances are closer to what they should be at normal operating temperature?

That is the main benefit, with big maintenance cost reduction. Any emission benefit is secondary.
Pre-heating is more energy efficient than running the engine to do the same thing.

Richard Scott · 18 Jul 2020

Bletchleyite said:
Many if not all diesel cars have a pre-heat, though of course with the much smaller engine it's fine to just power the glow plugs from the battery. On older cars like the diesel Series Land Rover I once had it was its own key position that you had to engage and leave there for 10-15 seconds (with a dashboard yellow light showing) before turning the rest of the way to start. Turning all the way too early would result in a sudden pea-souper as half the fuel tank just went straight out of the exhaust unburnt.

Oh, I remember the 2.5 engine in the later series as worked for Thames Water and they had one. Wouldn't start from cold even in summer if glow plugs not been on for 15 seconds minimum. Think they were direct injection engines and harder to start than the more common indirect injection that most smaller automotive diesel engines were at the time.

CW2 · 18 Jul 2020

The downside of requiring an engine to be pre-heated is the temptation to leave it idling rather than shutting it down. In diesel-hydraulic days there was often a blue haze over Laira depot coming from the host of Maybach engines idling needlessly for hour after hour.

py_megapixel · 18 Jul 2020

irish_rail said:
HsT MTUs need to be at 40degrees to start, and for 80x they should be at 45 degrees.

That's interesting; I had always assumed in the past that they could start from cold.

Do you happen to know similar statistics for Sprinters? I ask because their engines always seem to be left running even on quite long layovers.

themiller · 18 Jul 2020

The main benefit of pre-heating an engine is that it gets the lubricating oil up to temperature so that it can be pumped around the system before engaging the starter. This leads to less bearing wear.

superkev · 19 Jul 2020

A side note is that in my day many larger engines needed oil priming before starting. Not sure if this is now the case.
K

broadgage · 19 Jul 2020

The pre-heating of the whole engine block is common practice on railway locomotives and multiple units, it is not comparable to the use of glow plugs in a diesel car.
Glow plugs powered for less than a minute from the vehicle battery wont warm the engine block to any significant degree. They assist in starting by promoting full combustion of the fuel, not by pre heating the whole engine.

In very cold climates, diesel road vehicles DO need the engine block to be pre-heated for reliable starting. They are commonly fitted with "block heaters" that use mains electricity to heat the engine. Seldom used in the UK but common in polar regions. Better designs incorporate an interlock to prevent driving away whilst still plugged in. Some types also charge the battery.

PowerLee · 19 Jul 2020

We use a similar type of traction interlock on forklifts & scissor lifts where they have a onboard charger to stop you driving away with the unit still plugged in to the mains.

The better type of interlock design runs the traction interlock down the charger mains cable & requires it to be plugged in to its corresponding storage socket on the machine - the storage socket then completes the interlock circuit which will also cancel the dash warning message & allows the brakes to be released.
This type is also designed to always fail safe.

The basic type of interlock senses when there is mains power going in to the charger.
Issues are it just needs to be unplugged from the mains OR a power cut to allow traction - the design isn't foolproof or failsafe as the version above.

DelW · 19 Jul 2020

Richard Scott said:
I thought initially it was to reduce engine wear as a warm engine's tolerances are closer to what they should be at normal operating temperature?

I recall reading that Formula One engines have such tight tolerances that they are effectively seized solid when cold and can't even be turned over manually without causing damage. I believe they have cooling system connections which allow hot water to be circulated through the block to pre-warm them.

John Hunt · 19 Jul 2020

I have a vague memory that some trucks in Siberia(?) were started up at the end of their production line and continued running 24/7 thereafter. This was due to the fact that some metals can have the mechanical properties of glass at extremely low temperatures.
Is it just a vague old memory or could it be an urban myth?

hwl · 19 Jul 2020

broadgage said:
The pre-heating of the whole engine block is common practice on railway locomotives and multiple units, it is not comparable to the use of glow plugs in a diesel car.
Glow plugs powered for less than a minute from the vehicle battery wont warm the engine block to any significant degree. They assist in starting by promoting full combustion of the fuel, not by pre heating the whole engine.

In very cold climates, diesel road vehicles DO need the engine block to be pre-heated for reliable starting. They are commonly fitted with "block heaters" that use mains electricity to heat the engine. Seldom used in the UK but common in polar regions. Better designs incorporate an interlock to prevent driving away whilst still plugged in. Some types also charge the battery.

And Petrol engines in cold climes too...

hwl · 19 Jul 2020

John Hunt said:
This was due to the fact that some metals can have the mechanical properties of glass at extremely low temperatures.
Is it just a vague old memory or could it be an urban myth?

This bit is true - the most famous case of it being H&W's lack of quality control with the Titanic's rivets and in non metallic materials the gaskets on space shuttles (Challenger).

Dunfanaghy Rd · 19 Jul 2020

broadgage said:
The pre-heating of the whole engine block is common practice on railway locomotives and multiple units, it is not comparable to the use of glow plugs in a diesel car.
Glow plugs powered for less than a minute from the vehicle battery wont warm the engine block to any significant degree. They assist in starting by promoting full combustion of the fuel, not by pre heating the whole engine.

In very cold climates, diesel road vehicles DO need the engine block to be pre-heated for reliable starting. They are commonly fitted with "block heaters" that use mains electricity to heat the engine. Seldom used in the UK but common in polar regions. Better designs incorporate an interlock to prevent driving away whilst still plugged in. Some types also charge the battery.

I remember seeing block heaters on the shelf in a Shell Shop in Kirkenes. Obviously a fit yourself option.

Many years ago when I was on PW on of my colleagues had started out as a fireman at Reading (WR). He recalled manning the standing pilot one night - driver shut the engine down so that they could get some ZZZs, and when they came to the engine was too cold to start. Tow back to the shed required. Did this sort of thing actually happen?

Pat

Mitchell Hurd · 19 Jul 2020

I'm not sure if this is relevant to this thread but when I got on the 16:22 from Swansea back to Swindon at around 15:40 (was allowed out the cold drizzly rain), changing for Didcot Parkwaya, on the 09/03/20 (last train trip it was before now) the engines were turned off - this was just before I got on.

I thought it was therefore gonna get cold onboard - nope, the heating was still going even though the engines were turned off. Took me by compl Handy if stranded anytime if the engines get turned off if definitely going to be stuck for a while Engines were turned on at nearly 15:55.

Is this a way of pre-heating the IET's? With most DMU's (older than the IET's of course) it's either leave the engines on, use fuel and cause pollution or turn them off but everything's off and provide an uncomfortable environment onboard.

If this was requested when the 80x stock was ordered then that's fantastic of course!

Or do these have emergency batteries for hotel power?

I know this was a good few months ago but I only noticed this thread like today I think.

computerSaysNo · 19 Jul 2020

py_megapixel said:
That's interesting; I had always assumed in the past that they could start from cold.

Do you happen to know similar statistics for Sprinters? I ask because their engines always seem to be left running even on quite long layovers.

The engines in a HST can still be started from cold, however (as ScotRail found out when they first got them) that comes with a penalty of something like 200* engine run hours?

*Going by memory; someone else will probably have a much better idea.

computerSaysNo · 19 Jul 2020

Mitchell Hurd said:
I'm not sure if this is relevant to this thread but when I got on the 16:22 from Swansea back to Swindon at around 15:40 (was allowed out the cold drizzly rain), changing for Didcot Parkwaya, on the 09/03/20 (last train trip it was before now) the engines were turned off - this was just before I got on.

I thought it was therefore gonna get cold onboard - nope, the heating was still going even though the engines were turned off. Took me by compl Handy if stranded anytime if the engines get turned off if definitely going to be stuck for a while Engines were turned on at nearly 15:55.

Is this a way of pre-heating the IET's? With most DMU's (older than the IET's of course) it's either leave the engines on, use fuel and cause pollution or turn them off but everything's off and provide an uncomfortable environment onboard.

If this was requested when the 80x stock was ordered then that's fantastic of course!

Or do these have emergency batteries for hotel power?

I know this was a good few months ago but I only noticed this thread like today I think.

Could it have been a case of all engines bar one, were turned off (the remaining engine providing saloon lighting and heating, and running the pre heaters to the other engines when required)?

Engines needing to be pre-heated

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