John Knowles comments on the article, The Blue - Story of the Spirit of Progress, by Ian Brady in Australian Railway History 841, November 2007.

On p 430 of his article, Ian Brady suggests that the Spirit of Progress was one of the toughest runs (of a hand fired steam locomotive) in the world, presumably in one shift. He says that no fewer than seven to eight tonnes of the highest quality Maitland coal were used on each run (note, this reference is to each run, not difficult runs).

The task involved in the Spirit run can be analysed and converted to the power needed to do it. The measure which summarises both the power needed and the time over which it was developed is horsepower (hp) hours. One hp hour is one hp developed for one hour. (This is the same as kw hours, the unit for buying electricity - or electric power - in units of time, including electricity to power electric trains; one hp = 0.746 kw.) The power developed in the cylinders of a steam locomotive is called indicated hp (ihp), so ihp hours is the appropriate measure for comparing the Spirit run with others (see the Appendix for reasons why other measures of the output of a steam locomotive are not suited for this purpose).

The power developed by a locomotive comes from the coal fired. Coal consumed per ihp hour shows how efficient the locomotive was converting the energy in the coal to producing the ihp hours involved in moving the train.

It can be concluded from the analysis outlined below that an S, if it was an efficient locomotive of its time, should not have used as much coal as Ian claims on a Spirit run, at least good coal. From other evidence, Ian's figure for coal consumption seems too high. He gives no evidence about how it was determined that the Spirit run was one of the toughest (of a hand fired steam locomotive) in the world. It is presumably a guess. It is very doubtful.

The maximum load on the Spirit was eleven vehicles. If VR rated weights are taken, the parlor car, dining car, brake van and the eight carriages weighed 547 tons (one ton is 1.016 tonnes). These rated weights were for the vehicles loaded to their maximum capacity. The tare weights are given in a series of articles on VR coaching stock by the late L G Poole in ARHS Bulletins between June 1954 and March 1955.

The tare of the sitting cars was about 44.5 tons. Counting passengers at 16 to the ton, as usual on Australian railways at the time, their rated weights are roughly correct at 48 tons. The tare of the parlor car was 44 tons; as it had only 33 seats, its gross weight cannot have been more than 46 tons, compared with the rated 48. The tare of the dining car was 52 tons, and its rated weight 60 tons. Allowing for staff and supplies, the gross weight cannot have been more than 55 tons. The tare of the brake van was 35 tons. Even allowing for the large quantity of mail and parcels then moved by rail, as well as booked luggage, it seems unlikely that this vehicle carried the 20 tons needed to achieve the 55 tons rated weight. Ten tons is more likely.

This means that the gross weight of an eleven car train would have been 530 tons. If a DS mail man was substituted for a carriage, still within an eleven vehicle load, a greater load of mails, luggage and parcels would have been distributed over two vehicles, and the train been about ten tons lighter. The train was of course not necessarily always full of passengers. Nor was it always eleven vehicles. In "An Appreciation of the VR S Class Pacifics" in the ARHS Bulletin for June 2000, Lloyd Holmes mentions (p 220) observing the down SoP pass Seymour at around 8 pm, of ten cars for 500 tons or eleven for 550.

In his appraisals of the S class in the May 1963 ARHS Bulletin, Bill Abbott took the actual weight of loaded eleven vehicle SoP trains as between 505 and the full rated 547 tons. Bill had information on tare weight of VR carriages. He was very familiar with the VR and knew the loading of the train.

On the SoP, there was no power car to generate electricity for air conditioning and lighting. Electricity was provided by generators driven from the carriage axles by belts. It was stored in batteries for use when the train was stationary or running too slowly for the generators to provide sufficient power. The batteries were recharged when the train was running at higher speeds. This electricity was therefore generated by the locomotive pulling the train and turning the carriage axles. That generation used some of the energy in the coal consumed.

The following power figures are based on the northbound timetable speeds, the altitudes of the route, reputable figures for rolling resistance of the vehicles and locomotive, and for the machinery of the locomotive. They also allow for progressive reduction of the weight from the consumption of coal and water used on the 190.5 miles, 230 minutes (3.83 hours) run (one mile is 1.62 kms). The detail is given in the Appendix. Ignoring electricity generation through the axles in the first instance, and assuming still air, moving the 530 tons SoP from Melbourne to Albury required 4530 ihp hours. Running the empty cars back to Wodonga and the light engine movements at each end added about 100 ihp hours.

In the Here and There section of the ARHS Bulletin for May 1971, Bill Abbott said that driving the electrical system took 20 hp per car when the air conditioning load was at its greatest, adding 200 hp to the load on the locomotive for ten air conditioned cars. The load of 20 hp per car probably occurred on the hottest summer days. On balmy days when the outside temperature was about 18^oC, the power load was restricted to circulating the air and lighting. On cold days, there was a carriage warming load, bringing the total load to some intermediate figure.

In the carriage sheds at Melbourne and Wodonga, electricity for cleaning and lighting (and air conditioning for the cleaners) on hot days was supplied to the carriages from a stationary supply, and then switched off when the work was complete. The lighting and air conditioning were turned on in time for the kitchen staff to start work about three hours before departure. The air conditioning was in full operation when the train was placed at the platform before each run. If electricity was needed for say eight hours per one way run including the run itself, then the generating load on the locomotive for electricity becomes ten cars by 20 hp each by eight hours, or 1600 ihp hours. The total power requirement on the locomotive from shed to shed per one way trip on the hottest days was then 6200 ihp hours. On the actual run, 6100 ihp hours were produced, an average of 1600 ihp.

The fire in the S class was lit up from cold only after washouts and examinations, which occurred at Seymour. The lighting up was followed by runs on local trains to return the engine to Melbourne (see the article by Lloyd Holmes mentioned above). The fire was banked (ie pulled up into a heap of live coals below the firedoor) after each run on the Spirit, so that there were live coals on the grate until the next run. Before the engine left the shed the banked fire was brought to operating condition. The firebox probably contained over a ton of coal at the start of each run. But most of that was fired in anticipation of the run to be performed. Much less live coal would have been on the grate at the end of the run. The coal consumed by the movement of the train is the amount needed to refill the tender less the live coal left on the grate at the end of the run. The latter figure could be expected to be of just sufficient depth to resist draft during the movement of the empty cars, about six inches depth of live coal (there would have been ash beneath the live coals). On the 50 sq ft area of the grate of the S, that depth of live coal represented 25 cubic feet, or about 0.55 ton of coal. On that basis, the coal consumption associated with the ihp hours of the run is the amount of coal fed to the tender of the S at the end of each run less 0.55 ton.

Ian gives the coal consumption as 7 to 8 tonnes. If it was 7½ tons, or 6.95 tons after the 0.55 ton of coal not consumed in running, the consumption per ihp per hour for the 6200 ihp hours case would have been 2.5 lbs (lb is the abbreviation for pound; one pound is 454 grams). This is a very high rate of consumption for Maitland coal, of 13,600 BTU (British Thermal Units) per lb (this again comes from Bill Abbott, August 1974 ARHS Bulletin, p 171)(see below for how this coal consumption rate can be judged). It is also too much for the water consumption that Bill Abbott quotes, of 10,000 gallons for the run, because it means that only 6.4 pounds of water were evaporated per pound of coal, a very poor rate for such good coal and for a locomotive which on average was not worked especially hard (2240 lbs to the ton, 10 lbs of water to the gallon, 4.54 litres to the gallon; a BTU heats one lb of water one degree Fahrenheit or 0.55 degree Celsius). (Steam and water were also consumed in compressing air for the braking system, and some water was lost at the injector overflow). It would be expected that something nearer to 8 lbs water would be evaporated per lb of Maitland coal.

Bill Abbott quoted the coal consumption per trip as about six tons (Bulletins February 1963 p 30 and August 1974 p 175). That is also the weight of coal given by Geoff Williams in his article, "Wodonga Enginemen Working the Spirit of Progress" in Newsrail for March 2008 (p 74). Geoff has enlarged on the quantity for me. He interviewed two men who fired the S class engines when they were coal fired and used on the SoP.

They said that the coal consumption for the trip was at best between five and six tons, and at worst seven tons, depending on weather conditions and the driver. The drivers differed in their technique, and some were heavier on steam, and therefore coal, than the others.

The calculated 6200 ihp hours does not allow for unfavourable weather conditions. If six tons is taken as the best that could be achieved on days when 6200 ihp hours were developed, then 5.45 tons is to be debited to running. That tonnage represents 1.97 lbs per ihp per hour, and increases the evaporation to 8.2 lbs of water per lb of coal.

Now to judge what was an efficient coal consumption. There was little testing of Australian steam locomotives in a way which allows such judgement. There was however considerable scientific testing of British steam locomotives. The Duchess class Pacifics of the British LMS Railway had the same 50 sq ft of grate and about the same 54% of the gases of combustion passing the superheater elements as the VR S. The S should therefore have had roughly the same steam temperature at the same intensity of working as the Duchess, and about the same consumption of coal of the same heat value.

Burning South Kirkby coal of 13,700 BTU per lb, of much the same calorific value as Maitland, the Duchess used about 1.85 lbs of coal per ihp per hour when developing 1600 ihp at 51 mph. Over the speed range of 30 to 70 mph encountered in a run of the SoP, it used 1.85 to 2.0 lbs of coal per ihp per hour when developing that 1600 ihp. At these rates of working it consumed 7.7 to 7.85 lbs of steam per lb of coal fired; before auxiliaries and losses, about 8 lbs of water must have been evaporated per lb of coal. At 2300 ihp, coal consumption of the Duchess rose to 2.14 lbs per ihp per hour, and it consumed 6.9 lbs of steam per lb of coal fired; that means evaporating about 7.3 lbs of water per lb of coal fired All these figures depend on use of the live steam injector, as on the S. As Bill Abbott's 10,000 gallons figure for water consumption is not especially precise and not related to particular conditions, these figures provide only a general confirmation of the coal consumption. (As in the above calculation of coal consumption of the S, the coal consumption of the Duchess excludes light up coal.)

The superheat temperature of the Duchess was low for a modern locomotive, but its coal consumption could be expected to have benefited by about one per cent from its having a boiler pressure of 250 lbs compared with that of the S of only 200 lbs. The Duchess results were derived on a test plant, where constant conditions were set up for each steaming rate and speed. This too will have improved the Duchess results a little, compared with the variable conditions which prevailed on the VR North East line. (See British Railways, LTS Rugby, Report R13, Performance and Efficiency Tests of Duchess 46225.)

So the S class, consuming much less than seven to eight tonnes of Maitland coal, can be regarded as respectably efficient after all! But if it used more than six tons on hot days, that is possibly explained by the driver being heavy on steam, or adverse weather conditions.

A few more points on coal consumption and the work in firing, as related by Geoff Williams and to him by men who fired on the S when coal fired. The bunker was normally filled as much as possible, to avoid any supply problems. On the up, to Melbourne, the hardest sections were Chiltern, Glenrowan and Mangalore banks, and the climb from Seymour to Heathcote Junction. One man related that he never sat down on that last 28 miles section. On the down, the heaviest pull of the lot was the first, Glenroy bank, then between Donnybrook and Beverage, then Wallan to Heathcote Junction; then, north of Seymour, Glenrowan bank and Bowser to Bentons Hill, just before Springhurst. Where the gradients were easy, however, the work was moderately easy. The tenders were designed to be self trimming, ie for the coal to move forward as coal was fired, apart from a rear ledge.

At the end of each run, the fireman was observed going to the back of the coal space to bring forward enough coal to take the engine to the shed. Two tons could still have been present at the back of the coal space.

When Maitland coal was not available, Lithgow (NSW), Indian and State Mine (Victorian) coals were used. The SoP was usually delayed when these coals were used, by stops for attention to the fire, and the whole of the coal content of the tender was then usually used, or was even insufficient. The train once had to be hauled over the Murray River bridge into Albury, and on another occasion coal had to be borrowed from the shunting engine to enable the engine to return to Wodonga. It was these problems (mentioned by Ian on p 431) that induced the conversion of the engines to oil burning.

Calculations could be made for the effect of strong adverse winds, mentioned by Ian, if information was made available on intensity and direction. Information would also be needed on the effect on speed on critical sections. Almost all strong winds add to train resistance, the exception being those close to from directly behind. So on days of strong winds from other directions, if time was kept, ihp hours and coal consumption could be expected to have been higher.

In contrast to what Ian says on the matter, Geoff Williams says in his article in Newsrail that the special SoP crews prepared and hostled (put away) their own engine. The preparation included spreading the banked fire and building up the fire.

Was the SoP one of the toughest runs in the world for a hand fired locomotive? This has to be judged in terms of the amount of coal shovelled in the shift and the hourly rate of shovelling. Using 5.45 tons during the run on the SoP represents 1.44 tons per hour for 3.83 hours running time. For coals other than Maitland, adjustment has to be made for the different heat values (lower heat values mean a greater weight of coal for the same task).

The only other obvious candidate in Australia for such hard hand firing work on a passenger train is the C38 haulage of the down Melbourne Limited and Melbourne Express from Sydney to Goulburn, 140 miles. These engines were allowed to take 469 tons unassisted, the overall schedule was 3 hours 37 minutes, of which 13 minutes were stationary. On account of the large increase in altitude, this represents 4000 ihp hours, consumption of about four tons of coal, and 1.11 tons per hour from departure to arrival.

On the Royal Scot train of the LMS/British Railways, the 301 miles from London to Kingmoor shed just north of Carlisle was a crew shift, run non-stop. On a run on that train behind a Duchess class Pacific, the train weighing 480 tons, about 4600 ihp hours were produced in 3.75 hours to Preston, 5100 ihp hours in 4 hours and 5 minutes to Lancaster, and over 7000 ihp hours in 5 hours 10 minutes by the end of the shift at Kingmoor. An average ihp of 1360 was therefore developed for over five hours on the Royal Scot, and 1600 for 3.83 hours on the SoP on the hottest days when the air conditioning load was at its highest (analysis of the Royal Scot run by D H Landau, using slightly lower resistances than used to calculate the outputs of the SoP). The Duchess had a coal pusher which the VR S had not. Carriage lighting came through the axles. Carriage heating was provided by steam from the locomotive boiler, and is not allowed for. (The Duchess is somewhat lighter than the S as streamlined for the SoP, because it carried only 4000 gallons of water, being designed for use on a line with frequent troughs at which water could be picked up without stopping, compared with 13,000 gallons on the S, which had to carry water for the entire run.)

George Carpenter suggests that in Britain, about the same ihp hours as quoted for London to Carlisle would be required on shifts from London to Newcastle and Crewe to Perth, both hand fired. In France, he suggests that runs from Paris to Brussels would be at least as hard as the SoP, and the following harder: Tours to Bordeaux, Vierzon to Brive (en route to Toulouse), and Paris to Nancy. All of these runs were hand fired, and not all the engines used had coal pushers.

He remarked that many of the K4s Pacifics of the Pennsylvania Railroad in the USA were hand fired. They were larger than an S, but the work involved in a shift would have been reduced by the limiting of shifts there to about one hundred miles.

The late Bill Abbott reviewed the performance of S class engines in the ARHS Bulletin for May 1963, pp 72-73. The horsepowers he presented are allegedly rail hps, at the driving wheel rims, excluding the resistance of the machinery of the locomotive. The formula Bill used for the rolling resistance of locomotives and vehicles (see ARHS Bulletin April 1963), was 5 + .003V² lbs/ton. That was a crude formula, giving resistances far too high for most vehicles, and did not allow for the head end aerodynamic resistance of the locomotive. As there was only one head end for any length of train, that is a considerable omission in principle. The resistance to motion of rail vehicles is dependent on wheel and bearing diameters and bearing pressures, or broadly is lower per ton the higher the axle load, so one resistance figure for every ton is unlikely to be right. Further, rhp is not measurable except on a stationary testing plant, and is therefore not easily compared. It has no operating significance. Ihp is the measure of the output of a steam locomotive.

Bill's formula overestimates rolling resistance to such an extent that his rhp estimates are close to ihp, at least for the S class. I have been recalculated some of the efforts he quoted on the same basis as that used for all ihp estimates here (see Appendix).

The effort of S 301 on the Albury Express in 1937 from Broadmeadows to Heathcote Junction, 22.7 miles in 26.5 minutes, average 51 mph, is 2300 ihp, 2000 rhp and 1800 edhp. The last is the power at the drawbar, made equivalent to level track in the sense that the power needed to lift the weight of the locomotive up a gradient is included. I have assumed that at that date there was no air conditioning on the Albury Express. The effort in the second column of the table in the left column of page 73, S 300 on the SoP with 11 vehicles, 521 tons, from Kilmore East to Heathcote Junction is 1950 ihp, 1700 rhp and 1550 edhp.

The table in the right hand column of p 73 gives the dbhp of the S, the result of VR dynamometer tests, 2300 at 40 and 50 mph and 2150 at 60. I have assumed that these are edhp figures, the dbhp on level track; that these tests were made with the original bogie tenders, and with the engines unstreamlined; and that one third of the coal and water capacity of the original tenders had been used at the point of the test. Under those assumptions, the ihps corresponding to these edhp figures are about 2650 at 40 mph and 2800 at 50 and 60 mph. The figures are good for the dimensions of the engine. What is not known is for how long each edhp figure was developed. It is possible that the efforts were short, and drew on the thermal reserve of the fire or the boiler.

Ian Brady remarked (pp 430-1) that the B class diesel electrics could not match the S class (steam) on the hills on the SoP. Their installed power was 1500 hp, well below the ihps the S (steam) developed, but at 111 tons, they were only half the 222 tons weight of the streamlined S (steam) at the start of the run, and still much lighter than the 168 tons or so the S (steam) weighed at the end of the run after the coal and water consumptions given above. The later S diesel had 1800 hp, and weighed 114 tons. Although still not up to the power potential of the S steam, the lower weight was a considerable advantage. On the climb from Melbourne to Heathcote Junction, the lower weight saved about 175 hp in vehicle resistance and weight to be moved uphill. There was also about 160 hp advantage in the lower resistance between the power unit and the wheels of the S diesel compared with that between the cylinders and wheels on the steam S. Even so, the diesel S could not have equalled the 1800 edhp/2300 ihp effort of 301 between Broadmeadows and Heathcote Junction given above.

I saw the S class steam only in January 1952 by when they were oil burners. I was one of a party of school boys travelling from Brisbane to Melbourne. We had to travel on ordinary expresses as opposed to Limiteds, but I entered the Spirit carriages at Albury and saw the train leave there, an unspectacular event viewed from the platform (see photo on p 101 of ARHS Bulletin May 1971). Our following Albury Express was hauled all the way to Melbourne by C class 2-8-0 No. 21, limited to 50 mph, and it lost time. Apparently there were no spare A₂ or R class engines at Benalla or Seymour that day, a pity because the A₂ and R were allowed the line limit of 70 mph.

On the return, S 302 hauled the Albury Express throughout. It was a big train, and I was in a non-air conditioned carriage, able to watch the S ahead on curves on the climb to Heathcote Junction, the late afternoon sun shining on the driving rods and its blue streamlined casing. I remember its fast three cylinder exhaust, fast for its six feet coupled wheels. I have always regretted not having timed that train while it was still daylight. I had not then started that activity and was not aware the train was on a long easily curved climb as far as Heathcote Junction. That night the Spirit arrived Albury thirty minutes late hauled by 301, and had not been delayed by the Albury Express.

Later I travelled on the Spirit behind diesel electrics, and in the open saloon carriages built later on the same principles, mentioned on p 424 of Ian's article. On rail travel throughout the world, much of it in carriages of much more recent date, I have not encountered better sound proofing than in the carriages of the Spirit of Progress (cf Ian's remark on p 426 that on account of that sound proofing, he was unaware the train had started).

In 1972, I observed and travelled behind the S class 0-10-0T rack locomotives of the Lebanese State Railway on the 1.05 metre gauge line across the Lebanon Range to Damascus. This included long sections of 1 in 14.3 gradient. Their numbers were 301 to 307, so that four of their numbers duplicated those of the VR Pacifics. Their speed on the rack inclines was about a tenth of the maximum of their VR class and number counterparts.

The output of a steam locomotive can be measured in the cylinders, as above, or at the coupled wheel rims or at the drawbar. The coupled wheel rim measure occurs after the resistance of the machinery of the locomotive has been overcome. The drawbar measure occurs after the resistance of the locomotive as a whole has been overcome. As locomotives do not have the same machinery or are the same weight, or have the same tenders, while only a few are streamlined, the wheel rim and drawbar measures are unsuited to drawing conclusions on the efficiency of the coal consumption. This applies especially to the S, with its enormous tender (107.5 tons when full) and streamlined casing.

In calculating. the ihp hours for the timetabled run, the efforts for the sections Spencer St - Heathcote Junction - Seymour - Albury were calculated separately and added, mileages being zero, 33.25, 61.25 and 190.5, times being zero, 56, 88 and 230 minutes, respectively. A gain in altitude of 1115 feet was taken to Heathcote Junction, a fall of 581 feet to Seymour and a gain of 74 feet to Albury. Speed was taken as 30 mph at Heathcote Junction and 50 at Seymour.

The average weight of the S class locomotive was taken to be 208 tons on the first section, 191 on the second and 177 on the third. The weights of the train are given above.

The rolling and aerodynamic resistances of the locomotive and vehicles in still air were taken from the American Davis formula adapted to Imperial weights. This is

1.46W + 32.5n + .0336VW + kAV²

the answer being in lbs, W being the weight of the vehicle in tons, n the number of axles on the vehicle, V the speed in mph, A the cross section area in sq ft, taken as 110, and k being .0018 for the streamlined S locomotive, and .00034 for each of the vehicles of the train. (See W W Hay, Railroad Engineering 1953, and RP Johnson, The Steam Locomotive.)(One foot is 305 mm).

I have taken the machinery resistance of the locomotive as 9 lbs steam pressure or 2200 lbs at all outputs. There is little evidence on machinery resistance, and this figure seems to me to best summarise what there is (although not all agree - see article and letters in the Journal of the Stephenson Locomotive Society in 2000 and 2001). The American engineers Fry and Johnson (see reference above) recommended 20 lbs per short ton of adhesive weight, (ie 1% of adhesive weight) which in the case of the S is about 20% less (a short ton, the measure used in the USA, is 2000 lbs). A given machinery can be found under a wide range of adhesive weights, however, so such a rule cannot be satisfactory.

My thanks are especially due to Geoff Williams for relating his own experience of the working of the SoP and seeking out that of others. I also thank Jim Harvey, Michael Schrader, Doug Landau and George Carpenter for help with various parts of this note.

15th July 2008, altered title 18 August 2009