Steam v Diesel

There has been discussion on the Swanage Railway thread and elsewhere about the use of diesels as a cost saving measure. Has any real analysis beendone on the subject? I've just done a back of envelope calculation based on the NYMR. On a round trip between Pickering & Grosmont a steam loco uses about 1.5 tons of coal. If we take the price of coal as being £37o/ton that works out at £555. A diesel uses about 36 gallon at £0.80/litre or £3.64 a gallon so that works out at about £131 per round trip. The difference between the two is thus £424. Now the current return fare on the NYMR is £49 so, if 9 people decide not to travel because it is a diesel, that £424 saving is wiped out. That is not a huge number given the NYMR's experience of customer resistance to diesel.
Of course, it is not as simple as this as there are other things that need to be taken into account such as lighting up a loco and maintenance costs. The latter is going to be a huge variable, depending on what loco we are basing things on. A saturated 0-6-0 is going to be a lot cheaper than a superheated 4-6-0 to maintain, both in day to day service and at overhaul. It's also difficult to quantify the maintenance and overhaul costs of a diesel, especially the former as I'd venture to suggest that the majority of diesels are living on their last big railway overhaul and have yet to have the equivalent of a steam locos 10 yearly overhaul. However, with continued use, that will come. Again, on the NYMR, Cl.24 No.D5032 has been under overhaul for several years now and has had a huge anount of work done to it with an end not in sight. I can see future diesel overhauls rivalling steam for cost and, as I have said previously, replacement of many major components with like for like, such as engines, will not be possible once the stock of spares runs out.
Does anyone have any better information than i've provided with my back of envelope calculation?

 

There certainly are a large number of "imponderables" I would also suggest that those 9 at £49.50 is of course a different number on a line like Swanage that is only
5 .5 miles long (on a normal day). I would suspect that because of the length of the journey on the NYMR those 9 would be a lower number per train on a shorter line with say a 45 minute service interval, but maybe over a day could amount to the same thing?
You would hope someone in commercial on every line would know the answer.

 

Was there any feed back from ordinary passengers expecting a full steam service last year on the SR when the Wareham DMU ran alongside a single steam loco timetable, causing some travelling between Norden and Swanage not to take the DMU or the occasional 6 coach diesel/steam top and tail trains, there may not have been a formal survey? Going through facebook and trip review site comments might be possible?
However if the SR has already decided to use diesels peaktimes again to cut coal costs by publishing Summer 2024 timetables without any market research, then may not be worth it?

 

For railways who don't own their own fleet, I'd have thought the daily hire fees for each are potentially where further differences come into play? I don't know how it works elsewhere, but on the GWSR whilst steam locos are on a daily steaming fee, diesels are hired on a mileage basis.

 

How would overhauls be priced? Every steam loco requires a boiler ticket, which is a cost that is incurred to a large extent whether used or not, so any steam engine serviceable but not used is effectively costing money.

Of course, given finite hours of engine life for diesels, running them is the opposite.

Is there any difference in carriage-cleaning costs either way (does one flavour of soot spoil roofs more than the other?).

Spares inventory costs?

PW costs? Are they discernably different between the two? Bridge life?

 

I'm not completely convinced by the "stock of spares" argument. There are some diesel overhauls - the pioneer diesels at Bury, Paul Spracklen's class 50s - which have required huge investments of time and effort to achieve results. Meanwhile, steam used to be subject to similar arguments, but is now seeing new components manufactured that were beyond belief in the early days.

I'd also be reluctant to take D5032's overhaul duration as a clear signal of the difficulty of overhauls; I remember a Moors Line nearly a decade ago that suggested a return within "a year or two" was likely; I suspect labour prioritisation is as much a factor as cash or parts.

My own view is that public attitudes to diesel are heavily influenced by how the railway markets itself. If the marketing is "steam railway", there's no hint of diesel use, and then a diesel shows up for no obvious reason, then there's a significant let down. Whereas if the railway marketing includes diesels within what are visible, and makes clear which trains should be diesel worked, fewer customers will feel let down.

Is that really the case? My sense is that some of the major intermediate work on steam is required by time/use rather than watching the clock tick down, so I doubt the savings are so clear cut. And that's before getting into the trade off between steam use - effectively, a whole day - and diesel use, which can be nearly turn up and go.

 

Is this not a too simplistic argument here - taking the logic that the saving in fuel cost is the only variable would that mean the marginal cost of an extra steam round trip on NYMR will be £555 and thus only 12 ticket sales are required. Wouldn’t it be cheaper therefore just to haul one carriage with a steam loco?

 

I seem to recall (from statements when BR was phasing out steam) that the initial building cost of a diesel loco was something like three times that of steam, though that was largely balanced out by much higher availability. I don't know to what extent those respective first costs are reflected in overhaul costs, either then or now.

 

I'm not saying it's clear-cut, but if you were metaphorically standing in shed wondering whether to take out a steam engine or a diesel, the steam engine is on a countdown to it's boiler exam (which is a substantial cost, even if everything is fine) even if you don't use it, so every day it's not used are days when it's costing money (without chance to earn it). How you balance that against the increased wear caused by using is an interesting challenge for someone...

By contrast, the moment you fire the diesel up, even if it works perfectly, you are running down engine hours thus bringing it closer to an overhaul which also has a substantial cost even if nothing is wrong or worn.

 

May I point out that that rather depends on what job you are talking about? If you are talking about running both on 3 coaches on a flat line, then yes. If you are talking about maximum load at all times for the 0-6-0, which is likely to be barely noticed by the 4-6-0, and then throw in a bunch of hills, I suspect the "wear factor" will bring things closer to even. (Bearing in mind the sheer cost of overhauling a loco with 8/9 axles, as opposed to 3.)

 

As in everything there is no set answer, Diesels may be cheaper fuel wise, but how much to have a generator overhauled? engines often are not the expensive part, pistons run in liners, so the blocks often are not needing replacement, pistons, rings and bearings are quite common, being used in many versions of that engine, however it's the bits bolted on that are the killer when they go bang, or flash,
Diesels have their part to play, often they provide motive power at the turn of a key, assuming they are kept in serviceable condition, and will provide a means of running a service in the event of a steam loco having failed, or not ready to leave shed in time,
Dmu's of the mechanical type, are quite popular, because they provide a different aspect of travel, plus they fit into the same time frame as most preserved lines are trying to portray, so people might not mind them, plus kids of all ages want to sit in the front seats behind the driver, unless of course it's an SR thumper, in which case I'm not sure what the attraction is other than the thump,

 

What more do you need?

 

Genuine question, because I have no knowledge in the area. How much work is required on a diesel loco require when it engine hours are up?. I have a photo I took at Swindon in the late 60s that shows hydraulics stripped to a shell for overhaul, but was that actually necessary ?

 

Steve is 36 gallons a round trip for 25278 or 47077 ..because similarly to 29 and 92134...consumption varies ...?

 

Varies...some owners work on exam cycles---six As,a B ,six As,2nd B etc and after 6 Bs a C.
Other owners appear to fire fight faults as they occur.

 

When I worked on Balmoral, her engines were the original Newburys and we managed either to get spares made liners, piston rings etc or overhauled in the case of the fuel pumps. Unlike the Sulzer & English Electric engines used in 60's loco's these were nothing like anything in use at the time.

Admittedly a 300rmp two stroke is a different beast to a 750rpm turbocharged 4 stroke but on the face of it its possible

 

Steam has a mixture of time-based and mileage-based costs. For example, the boiler has to be at least stripped and inspected - probably leading to at least some level of overhaul work - every ten years (in addition to annual steam tests). Whereas much of the mechanical condition is mileage-based. So there is a lot of thought into trying to get those two things to co-incide. The ideal is that the loco needs a mechanical overhaul at the same time the boiler would be lifted anyway. For us, a pre-group saturated loco that probably means it needs mechanical attention after about 40-50k miles, which means targeting around 4-5k miles per year. Any more, and the loco will likely be mechanically worn before the boiler needs attention; any less and you are still committed to an overhaul but have amortised the cost over too few miles. (*) For a more modern BR standard you might aim to get 75 - 80k miles in the ten years, though the subsequent overhaul is then likely to be more expensive. It makes the calculation of per seat mile cost of overhaul quite complex - though I suspect the empirical assumption that BR Std 4 tanks are ideal for most railways is probably pretty close - the right combination of (relative) simplicity and good haulage capacity. An Ivatt 2MT tank likewise for smaller lines.

Your own workshop facilities must also have a big impact on costs - i.e. whether you are able to overhaul in house, or you send locos away for overhaul.

(*) There is an alternative overhaul philosophy which, from looking at various annual mileages seemed to be in vogue at the Bluebell some years ago, and on the Isle of Wight more recently, which is to run very low annual mileages - perhaps as little as 15 - 20k miles in ten years. The benefit is that you need to do very minimal mechanical work at the first overhaul - in other words, the "first" ten yearly boiler overhaul is something like an intermediate mechanical, after which you do a second stint in traffic before a "full" mechanical overhaul next time round.

I suspect a lot of the differences in steam costs from different models come down to your perception of risk. If you own your own locos and pay the overhaul costs, a £300k overhaul that spirals into £500k for unforeseen additional complexities is a big risk - whereas if you are a hirer, you pass that risk back to the owner. OTOH, you leave yourself exposed to being unable to hire a loco because nothing is available, which is pretty service-limiting! So it comes down to which set of risks do you feel is preferable.

(In other words, if I aim for 50k miles between overhauls by doing 100 days per year at 50 miles per day and the the overhaul changes from £300k to £500k, my per-mile loco cost attributable to overhauls has risen from £6/mile to £10/mile. Whereas if you have agreed a daily rate of £400 per day for the same 100 days / 50 miles, you are paying £8/mile but at least it is consistent and you aren't going to have any price shocks.)

Tom

 

Tom sets it out way more clearly than I could.

The interraction between fixed and use-related costs must be one of the many things that give the financial team grey hairs

 

I can probably add a bit to this.

Spa Valley operates steam and diesel traction so I see the costs of both. Our visitor numbers don't differ overly as our mainstream income is dining but I know if was going for a day out and wanted steam and got a diesel I didn't like I'd be rather deflated.

Steam locos are generally somewhere between £500 and £1500 per day steaming fee depending on the loco. Some groups have an arrangement of a fixed fee per year for unlimited use, you could in theory pay £50k a year and use the engine say 10 times because you don't need to use it anymore and that cost is then £5,000 a day whereas if you used it 100 times it becomes £500 a day.

It isn't just coal, it's water and oil/paraffin too plus the consumables like brake blocks, filters, corks, trimmings, tools etc that the operator pays for so the actual cost of operating per day isn't just the steaming fee and the coal.

Diesel locos are anywhere between £3 and £10 a mile I've found. Some are on a day rate, anywhere between £100 and £500 per day. Fuel is currently about 85p a litre, if driven economically a class 25 or 33 will do a gallon per mile. Something a lot bigger with a larger power unit is naturally going to burn more fuel.

The cost of overhauling diesels is already on par with steam if you have a complete rebuild. The locos at Spa have had hundreds of thousands spent on their bodywork, engines and electrical equipment over the years.

What is the true cost operating a railway, it really depends on everyone's interpretation of it some budget a day rate for a loco even if the railway own it so when the 10yrs is up or the generator flashes over it's got money to fix it. Some don't and then we see locos both steam and diesel laid up around the country.

 

Just to chuck in the mix, was on the NYMR today and there was quite a lot of disgruntled folk this morning about the diesel haulage on the Whitby section, lots of folk turned out for the 1000 expecting steam, certainly a couple of bays in our carriage who were of the “if we’d have known we wouldn’t have bothered” opinion,

All the steam services on the Grosmont-Pickering section looked well filled, our train certainly was.

I understand from a member of staff that the steam loco had an issue with some of its mainline kit, so wasn’t able to run the Whitby service.

Chris