Reliability of 8MB275T Engines as found in Class 60s and the MV Isle of Mull

[Highland37]

Sorry if this has been asked elsewhere.

I was on the MV Isle of Mull yesterday which has sailed to Mull since 1988 in a fairly intensive pattern and the Mirrlees units must have huge hours on them.

But I hear the units in the Class 60 sometimes fail. I am presuming that the units on the Isle of Mull have much higher hours on them so why do the rail units tend to be less reliable?

 

[Jamesb1974]

Deleted

 

[furnessvale]

All engines, regardless of design or manufacturer can fail.

Added to which, rail diesel engines are subject to far more thermal stresses with the constant cycling between idle and full load.

 

[fgwrich]

Added to which, rail diesel engines are subject to far more thermal stresses with the constant cycling between idle and full load.

Incidentally one of the reasons why the Paxman Valenta engines became rather knackered (and had coolant issues from fairly early on), They'll happily run fine in a Ship for hours and hours, but on a Paddington to Oxford HST where they'll be running fast to Slough, stop, Fast to Reading, stop, Fast to Didcot, stop then poss stops at Culham, fast to Oxford = Idle/Full/Idle/Full. Compare that to say running on mid to full for in a Ships power plant for 12 or so hours per day.

 

[Elecman]

Possibly also the vibration from running on dry land on steel rails with steel wheels won't help either

 

[najaB]

Possibly also the vibration from running on dry land on steel rails with steel wheels won't help either

I doubt that's as big an effect as the thermal cycling. Ship's engines also have access to lots of nice cool water and don't have to bother with complex radiator/forced air systems which get blocked up/coated in grime.

 

[gimmea50anyday]

With the invincible class carriers the Valentas powered the ship electrical supply and therefore ran at a steady and constant power level as opposed to the stop start nature of power car running. Familiarity with the engine is why Devonport overhauled the HST power units

 

[Highland37]

Thanks for the replies.

I am guessing that the rail units in the Class 60 have much less hours on them than the ones in the Isle of Mull but due to the running cycle those hours are harder and the more complex cooling an issue.

Are they both using the same diesel? The exhausts on the IoM look much, much bigger than on a 60 so I am guessing that could also be an issue.

 

[D1009]

Compare that to say running on mid to full for in a Ships power plant for 12 or so hours per day.

I don't think that's the case with ferries which stop many times a day.

 

[Shaw S Hunter]

I don't think that's the case with ferries which stop many times a day.

Nevertheless the thermal cycling is much less severe, aided by less cramped installation.

When BR was busy withdrawing and scrapping all those small shunters many of the diesel engines found further use as replacement power units for trawlers so the connection between railways and shipping is not new.

 

[Highland37]

In the case of the MV Isle of Mull, it basically low power for 5 minutes, full power for 45 minutes and low power for 5 minutes followed by 20 minutes shut down and then shut down overnight.

I take the point about on board engineers and I think they have maybe be used on a heavier grade of diesel over the years.

 

[randyrippley]

the real question should be.....
after the fiasco which led to the Mirrlees engines in the Class 30 being replaced by EE units, how could anyone later choose Mirrlees over Ruston when specifying the Class 60?
Given BR's successful use over many years of EE designs (which were the basis of the Ruston diesels), selecting the Mirrlees design was a brave act!

 

[furnessvale]

In the case of the MV Isle of Mull, it basically low power for 5 minutes, full power for 45 minutes and low power for 5 minutes followed by 20 minutes shut down and then shut down overnight.

In railway terms, in the UK at least, that sort of cycle would be very benign.

 

[Highland37]

In railway terms, in the UK at least, that sort of cycle would be very benign.

It does suggest then that the 8MB275T is not the best rail unit as many other units seem to last longer. Some EMD units and EE ones are much much older with a similar cycle.

I love the sound of the turbos spooling up on the Mull.

 

[Jamesb1974]

Deleted

 

[birchesgreen]

The engines of the class 30s were sent back to Mirrlees who then resold them for maritime use. I wonder if any ex-class 30 engines are still chugging around in any old trawlers?

 

[61653 HTAFC]

the connection between railways and shipping is not new.

Didn't one of the preserved 55s receive a replacement engine (or two) from a submarine? The Napier Deltic engine having been developed for maritime use initially.

 

[BestWestern]

Thanks for the replies.

Are they both using the same diesel? The exhausts on the IoM look much, much bigger than on a 60 so I am guessing that could also be an issue.

Ships' funnels tend to contain a cluster of far smaller internal exhaust pipes, though. Presumably the output from the engines on an individual basis would be broadly similar, albeit with potentially heavier exhaust if the grade of fuel burned was less refined for the marine application.
--- old post above --- --- new post below ---

The engines of the class 30s were sent back to Mirrlees who then resold them for maritime use. I wonder if any ex-class 30 engines are still chugging around in any old trawlers?

I understand that the AEC engines removed from London Transport RT buses during mass withdrawal were popular for reuse in small vessels in the far east.

 

[fgwrich]

Ships' funnels tend to contain a cluster of far smaller internal exhaust pipes, though. Presumably the output from the engines on an individual basis would be broadly similar, albeit with potentially heavier exhaust if the grade of fuel burned was less refined for the marine application.
--- old post above --- --- new post below ---


I understand that the AEC engines removed from London Transport RT buses during mass withdrawal were popular for reuse in small vessels in the far east.

Funny enough, a lot of the Gardner engines recycled from Bristol REs & VRs have also found there way into Marine use as well. It's quite nice hearing the sound of an ex RE 6HLXB / HLX on full boar disappear out into the distance on a Trawler or Yacht - There's still a 6XLB powered trawler still in use up in Northumberland too!

 

[AnonymousUser1]

Added to which, rail diesel engines are subject to far more thermal stresses with the constant cycling between idle and full load.

and don;t have an engineer and fitter ( or multiples there of ) travelling with them unlike all but the smallest commercial vessels ...

 

[Highland37]

Ships' funnels tend to contain a cluster of far smaller internal exhaust pipes, though. Presumably the output from the engines on an individual basis would be broadly similar, albeit with potentially heavier exhaust if the grade of fuel burned was less refined for the marine application.
.

The exhausts on the Mull are very much bigger than a class 60. At least 18 inches I would guess.

 

[Shaw S Hunter]

Didn't one of the preserved 55s receive a replacement engine (or two) from a submarine? The Napier Deltic engine having been developed for maritime use initially.

I believe the naval vessels which used the Napier Deltic were high speed patrol boats. Offhand I don't remember too much more but I don't think they were particularly numerous. And Prince Charles' first command may have been one. I'll have to do some research....

 

[ac6000cw]

As far as I know, both the Napier Deltic and the Paxman Valenta were originally developed for maritime use - at least some of the development costs were funded by the MoD in both cases. Naval use is also one of the reasons why they are largely built from aluminium - minesweepers need to be made from non-magnetic materials (to avoid setting off magnetic mines).

MTU is of course a major maritime engine supplier that has branched out into the rail market more recently, and EMD two-stroke diesels have long been popular for maritime use in the US and Canada - mechanically simple and very reliable engines.

 

[Peter Mugridge]

I believe the naval vessels which used the Napier Deltic were high speed patrol boats. Offhand I don't remember too much more but I don't think they were particularly numerous. And Prince Charles' first command may have been one. I'll have to do some research....

I thought they were minesweepers?

 

[Jamesb1974]

Deleted

 

[Shaw S Hunter]

I believe the naval vessels which used the Napier Deltic were high speed patrol boats. Offhand I don't remember too much more but I don't think they were particularly numerous. And Prince Charles' first command may have been one. I'll have to do some research....

As far as I know, both the Napier Deltic and the Paxman Valenta were originally developed for maritime use - at least some of the development costs were funded by the MoD in both cases. Naval use is also one of the reasons why they are largely built from aluminium - minesweepers need to be made from non-magnetic materials (to avoid setting off magnetic mines).

I thought they were minesweepers?

It turns out we've all remembered different parts of the story. Initial R&D was indeed funded by the RN and took a lead from German practice, indeed the first fitting was in a captured German patrol boat. The first use was in the Dark class of fast patrol boats (18 RN, 8 export), and the Norwegians also developed a similar vessel. Their predominantly aluminium construction did indeed lead to them subsequently powering minesweepers, initially the Ton class (115 RN - many later sold on, 4 export) and later the still extant Hunt class; 13 of these were built, 4 have been sold on and one is now a trainer at HMS Raleigh but there are still 8 Deltic powered vessels available for use around our shores. According to the technical description on Wikipedia the timing of cylinder air movements means all Deltic engines have a similar exhaust note, though of course silencing arrangements will vary, so if you hear a distinctive drone offshore do not be surprised! HTIOI

 

[gimmea50anyday]

And lf course Valentia's were used as auxiliary power units in lusty, ark royal and invincible (that's Ro6, Ro7 and Ro5 not 50 037, 50 035 and 50 025!)