Engine/driving hours

[Stigy]

Something that I’ve recently wondered about, and that I don’t recall ever being told, is about the engine hours on DMUs. I had a look at a couple recently on 16x units and they were both roughly at 125,000 hours.

So my questions;

What specifically do these hours mean? Are they the literal run time off the engine, whenever it’s running?

How are service intervals determined? I assume judging by the hours I’d seen, that the hours are reset after every “service” of the engine and each unit has a max number of engine hours between services?

On a side note, how are other serviceable items renewed (brakes for example)? Is it just a case of inspecting them when they are in for routine work? Obviously with a road vehicle covering on average 12k a year things like brakes are easy to monitor between services or on an ad-hoc basis, but with trains travelling hundreds of thousands of miles each year, I wonder how efficient items are picked up?

Thanks all!

 

[TRAX]

Yes on vehicles engine hours usually mean the time, to the minute, the engine has been turning since new or a reset.

 

[GC class B1]

Something that I’ve recently wondered about, and that I don’t recall ever being told, is about the engine hours on DMUs. I had a look at a couple recently on 16x units and they were both roughly at 125,000 hours.

So my questions;

What specifically do these hours mean? Are they the literal run time off the engine, whenever it’s running?

How are service intervals determined? I assume judging by the hours I’d seen, that the hours are reset after every “service” of the engine and each unit has a max number of engine hours between services?

On a side note, how are other serviceable items renewed (brakes for example)? Is it just a case of inspecting them when they are in for routine work? Obviously with a road vehicle covering on average 12k a year things like brakes are easy to monitor between services or on an ad-hoc basis, but with trains travelling hundreds of thousands of miles each year, I wonder how efficient items are picked up?

Thanks all!

Second generation DMU engines and transmissions are warranted for 500,000 miles. I do not know of any maintenance purpose for the engine run hours. It is a while since I was involved in the maintenance specifications for these units so I am relying on memory but the principles underpinning their maintenance is the same for all Railway Rolling Stock. As you state the annual mileages for these vehicles are much higher than domestic road vehicles so the time between examinations must therefor be much shorter. The maintenance regimes I am familiar with are based on a sequence of examinations (known as Routine Maintenance and carried out at the maintenance depot while the units are in traffic), and the sequence begins with a Fuel Point examination which is based on the range of the fuel tanks and usually about every 2 days and may be carried out at suitable locations away from the maintenance depot. This Fuel Point examination includes a number of checks as well as refuelling but does not normally include measuring the brake block thickness. The next examinations will be scheduled at a maximum mileage or time interval since the last examination, similar to a car service interval. The subsequent examinations will include additional examinations and on higher mileage (numbered or lettered e.g. C, D etc ) examinations some components that are reaching a mileage or time when failures may became more likely will be changed.
Major overhauls will be carried out when the units reach a mileage/ time that they need to be taken out of service for more time consuming work such as repainting, corrosion repairs, air conditioning system overhaul where this is not modular.

 

[eastwestdivide]

Engine hours is also a common way of determining service intervals on construction equipment and similar - something like an excavator might not do many miles, but will be working hard digging, grabbing, swinging, dropping, adjusting position etc.

 

[Stigy]

Interesting, thanks for the insight.

 

[XAM2175]

Engine hours is also a common way of determining service intervals on construction equipment and similar - something like an excavator might not do many miles, but will be working hard digging, grabbing, swinging, dropping, adjusting position etc.

Agricultural stuff too, tractors and the like.

And aircraft, obviously

 

[gingertom]

way back in the far distant past I did some maintenance schedules (oil & filter change) on genset engines. These ran at a constant RPM so the only metric used to determine service intervals was engine run time. This didn't take into account whether it was loaded with one light bulb or the whole industrial machinery- fuel consumed obviously would vary with load but the plant was operating 24/7 so was never really that lightly loaded. IIRC it was something like 1,000hours between services, about every six weeks.

 

[43096]

Second generation DMU engines and transmissions are warranted for 500,000 miles. I do not know of any maintenance purpose for the engine run hours.

Certainly on HST power cars, engine maintenance has been done based on engine hours. For the Valenta and VP185 fleets it was based on TOPS hours, whilst for the MTU 4000s it uses the hours recorded on the MDEC engine management system. There is a discrepancy on this, as TOPS hours is based off hours in traffic (so doesn't include time spent idling on depots etc.) whereas the MDEC data is all engine hours.

 

[BigB]

If hiring a loco to a FOC for use on say infrastructure or monitoring trains, there is a lot of sitting stationary, and so mileage alone is no indication of the use of the engine. Similarly an ETS equipped loco on hire may be used for warming up carriages for several hours daily but never turn a wheel, so you need to have visibility of both hours and mileage.
Essential maintenance for engines such as an oil change is based on hours.

 

[Grumpy Git]

I don’t think it’s engine hours in ‘real time’ that are recorded, but based on a certain engine RPM.

For instance, if a loco is sat idling/ticking-over for an hour, then it will record fewer ‘hours’ than if it’s working at full power speed.

I remember when driving agricultural tractors in the 1970’s that the tachometer (rev counter) had the words;

‘Engine hours at 1,000 RPM’ printed on it.

 

[alf]

Surely the real measure of wear & oil consumption is engine revolutions..revs.
That must be very easy to measure & record.

 

[supervc-10]

Agricultural stuff too, tractors and the like.

And aircraft, obviously

Aircraft (in particular pressurised aircraft) tend to go by cycles and hours. A Ryanair 737 doing 1-2 hour hops around Europe will be doing much higher cycles per flight hour than, say, American Airlines flying their 737s on lots of 4+ hour long routes across the USA. A cycle is a takeoff and landing. There isn't much stress on the airframe sitting in cruise but taking off and landing (and the associated pressurisation cycle) is what stresses the airframe. The engines however do get serviced by hours (although I'm sure cycles are factored in too).

It's a bit like how modern cars can have 'variable' servicing. In my old Seat, I was doing ~15k miles/year of 80% motorway- very low stress on the car. The computer pushed the service interval out to every 18k miles, as the driving I was doing involved few cold starts and not much stress. The same car being driven around town constantly, the service interval would be 10k miles, because someone driving like that is putting more stress on the vehicle. I had that car from new to 3 years old, and did 53k miles in it. It was still on the original tyres and brakes, because the driving I was doing was so gentle on it that they were fine. Had a good amount of tread left on the front tyres too!