Mammoth locomotives for hauling huge freight trains
4000 Class “Big Boy” 4-
TO railroad fans, the initials “UP” have always stood for Union Pacific, but to students of mechanical engineering those same initials recall the phrase “unlimited power”, and there is no better way in which to describe Union Pacific locomotive power practice.
The Union Pacific was part of the first American transcontinental railroad. Particularly in respect of locomotive policy, its progressive management enjoyed a reputation for research, for innovation and for an ability to operate a stud of locomotives representing the ultimate in technical development and capable performance. Thus it was no accident that Union Pacific power was invariably ahead of the company’s current requirements; that freight trains ran on schedules which were highly satisfactory to shippers; and that the combined tonnage and speeds achieved resulted in an operating ratio which even the most exacting accountant termed efficient.
The “Big Boys” were no isolated achievement. The research and development that went into their construction came from a wealth of experience and a long line of remarkable locomotives. By 1930, the railroad had in service almost one hundred 4-
The next significant development came in 1936, when the “Challenger” 4-
In parallel with the development of the 4-
Costwise, the 800s effected the economy required by management. During the first year of operation, savings of $1¼ million were turned in, being attributed to more-
Many of the features of the 800s later came to be employed on the “Big Boys”. The 4-
Thus was the stage set for the introduction in 1941 of the first of the “Big Boys”, of which 25 were built by Alco at Schenectady, New York, before the end of the war. The huge 4-
At the close of the nineteen-
Late in 1940, Otto Jabelman decided that not even the 40 “Challengers” would eliminate the older Mallets from double-
Previous wheel arrangements all carried distinguishing names—Mountain (4-
The first engine, No 4000, was handed over to the railroad at Council Bluffs on September 4, 1941, and immediately went into freight service between Cheyenne and Ogden hauling tonnage trains over the severe mountain grades. The engine arrived on the Union Pacific not without incident. Schenectady is in the eastern seaboard state of New York and never previously had anything weighing 605 short tons in working order had to be worked the 1,500 miles from there to the Union Pacific. It proved to be a slow and tedious journey.
One of the more delightful, though possibly apocryphal, stories of those early days with No 4000 occurred during a luncheon the Union Pacific board gave to the Chamber of Trade and business community in Omaha to celebrate the arrival of the first “Big Boy”, which was by then in freight service west of Cheyenne. There had always been tremendous rivalry between the railway and its competitor, the Northern Pacific, which had an equal reputation for operating large locomotives and immensely long freight trains. At that date the Northern Pacific had been claiming the largest locomotive, in its Yellowstone 2-
Towards the end of the luncheon the Union Pacific president rose to his feet to toast the “Big Boy”, concluding his speech “so I am now proudly able to say that once again the Union Pacific have the largest locomotive on earth”. His words were particularly apt, because at that moment the first “Big Boy” had derailed at a place where there was a “low fill” (or embankment), leaving the divisional master mechanic scratching his head as to precisely how something of that weight should be “put back on”.
The 4000s had a wheelbase of 117 ft 7 in and an overall length of 132 ft 9¼ in, engine and tender. This extreme length necessitated installing 136 ft turntables in the roundhouses at Cheyenne, Green River, Laramie and Ogden, all terminals on the main line to the Pacific coast. At other places the engines were “wyed”, or as we would say, turned on a triangle, while at one or two terminals with only a standard length table the engines were “jack-
THE “BIG BOY” LOCOMOTIVES featured on a stamp series “Leaders of the World” issued by Tuvalu in 1985.
All 25 “Big Boys” were put into pool service between Cheyenne in the east and Ogden in the west, representing the mountain divisions of the Union Pacific main line. The Union Pacific divides into two distinct parts. At the eastern end the railroad starts at Council Bluffs, Iowa/Omaha, Nebraska (two cities facing one another across the Missouri river) and runs for 528 miles across the rolling prairies of Nebraska to Cheyenne in the extreme south-
Westward out of Cheyenne, the first 31 miles required westbound trains to be lifted 1,953 feet, to an elevation of 8,013 feet at Sherman summit, on a ruling grade of 1 in 64½ and an average of 1 in 85. The distance over the Wyoming and Utah divisions from Cheyenne to Ogden is somewhat less than so-
The “Big Boys” were not often noted in passenger service, although they were designed for speeds of up to 70 mph. During the war they were known on troop trains and in the mid-
While most aspects of railroading in North America are large in the widest sense of the word, nonetheless, one was still not quite prepared for the sheer size and bulk of a “Big Boy”. In the United States, mechanical dimensions tend to be given in small units such as pounds and inches— possibly to make the resultant large figures larger still, or more probably because most formulae and calculation require that form—with an impressive result in the case of the 4000s. The locomotive alone weighed 772,000 lb and the total with tender in working order was 1,209,000 lb. The sheet length of 132 ft 9¼ in carried on 16 68 in drivers and two four-
The four cylinders, admittedly not as impressive in size as their low-
At one stage in design of the locomotive, boosters were considered, but they were not used. The boiler varied in diameter between 95 in and 105 in, with a welded firebox 235 in by 96½ in, and a combustion chamber 112 in in length. It is wonderful what can be done with a loading gauge of 15 ft 6 in height and 10 ft 9 in width and an axle load of 30 short tons running on 133 lb rail! In accordance with normal Union Pacific practice at that date, a live-
Experiments in oil-
The two engine beds on the 4-
One of the more novel—for 1941 — innovations was the running gear arrangement, in which a system of lateral motion control was designed to fit all wheels to the rails, thus to reduce binding on curvature to a minimum. In addition, it adjusted the wheels to vertical track differential with minimum disturbance to the weight distribution of the locomotive. The effect was to produce a stable engine on straight track but with the ability to adjust to curvature. Consequently the “Big Boys” used to “heel to the curves” smoothly without the tell-
The punishment to which the “Big Boys” were subjected is beyond anything known in this country, so that a word or two on their performance will not be out of place. One hot July day in 1949, westbound extra freight consisting of ninety-
Engineer Hooker of the “Big Boy” started by using 65 per cent cut-
The “extra freight west” restarted 12½ minutes after arriving there and achieved 14 mph in six minutes nine seconds, when the 4-
The description of that particular run has been included to illustrate the way in which the 4000s could be operated under arduous conditions. It is not typical of Sherman in that the pilot, No 3819, was not steaming well and therefore contributing less than would normally have been expected.
The “Big Boys” truly lived up to their name and reputation. Perhaps the most memorable sight of all was the view forward from the cab of a 4-
THE “BIG BOY” IS A GIANT 4-