NYC: Big Four / Boston & Albany / Canada Southern / Lake Shore & Michigan Southern / Michigan Central / New York Central / Pittsburgh & Lake Erie / St Lawrence & Adirondack 4-4-2 "Atlantic" Locomotives in the USA


Class Details by Steve Llanso of Sweat House Media

Class I - 20 1/2""//Ia (Locobase 5292)

The data comes from a reproduction of the New York Central's 1902 Locomotive guide found on [] (visited December 2002).

The guide notes that part of the order was delivered with 20 1/2" diameter cylinders. Those are shown in this entry. Also represented are the 25 Ias from 1902. These were identical except for a front truck wheelbase increase of 3", which increased engine wheelbase to 27' 6".

See Locobase 5293 for the 21" version. According to the guide, these classes were fitted with traction increasers that increased the weight on the drivers by 10,000 lb. Engine weight was redistributed from the leading and trailing trucks.


Class I - 21 1/2""/I-10 (Locobase 5293)

The data comes from a reproduction of the New York Central's 1902 Locomotive guide found on [] (visited December 2002).

The guide notes that part of the order was delivered with 21" diameter cylinders. Those are shown in this entry. See 5292 for the 20 1/2" version. According to the guide, these classes were fitted with traction increasers that increased the weight on the drivers by 10,000 lb. Engine weight was redistributed from the leading and trailing trucks. Firebox heating surface included 27.09 sq ft of arch tubes.

Arthur Curran, writing in "Yesterdays on the New York Central," Railway & Locomotive History Society Bulletin #1 (1921), p. 9, notes that Arthur Waitt had designed a Ten-wheeler, but quickly decided he needed a new arrangement for his express engines. He designed the "Central Atlantic", which, Curran says, "[i]n neatness of general design and refinement of detail these ...engines were pre-eminent and unique. Their performance on the road was characterized by a consistency and smoothness of running that won for them the approbation of the men who ran them and the passengers who rode behind them."


Class I-1 (Locobase 4092)

Data from NYC&HR 9 - 1905 Locomotive Diagrams including Subsidiaries supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange collection. See also able in Paul T Warner's article on Atlantics in the Railway & Locomotive Historical Society Bulletin #62 (1943, p 20); American Engineering and Railroading Journal's July 1904 table shows additional data; and report of Tests of Locomotives at the Louisiana Purchase Exposition published in Transactions of the American Society of Mechanical Engineers (Volume 27 - 1906), pp. 630-632. Works number was 29418 in December 1904.

Before giving up entirely on compound non-articulated locomotives, the New York Central conducted a trial between this Cole four-cylinder balanced compound, Baldwin's version of the same basic concept (Locobase 5384), and the reigning I-class simple-expansion Atlantic designs such as Locobase 5292.

Firebox heating surface included 28 sq ft (2.60 sq m) of arch tubes and each set of 1 HP and 1 LP cylinder was supplied by a long 14" (356 mm) piston valve. Both HP cylinders were located inside ahead of the smokebox and drove on the crank of the lead axle while the LP cylinders outside and alongside the smokebox drove on the second axle.

It appears to have been unsatisfactory, because the Water-Level Route almost immediately ordered dozens of two-cylinder simple 4-4-2s from the same builder. The I-1 was scrapped in the same month (November 1913) as its Baldwin counterpart.


Class I-10 (Locobase 5547)

The data comes from a reproduction of the New York Central's 1930 Locomotive guide found on [] (visited May 2003).

These were superheater rebuilds of the I-class Atlantics built in considerable numbers in the first few years of the 20th Century. All traded 175 small tubes for 28 flues and all had 12" (305 mm) piston valves.

Most of the 4-4-2s received this retrofit during the 19teens. had been applied to the following quantities of I-10 variants:

I-10A (11)

I-10 (5)

I-10D (4)

I-10F (34)

I-10G (34) - trailing tenders with 7,000 US gallons (26,495 litres) of water and 12 tons (10.9 metric tons) of coal. Loaded weight came to 148,800 lb (67,495 kg).

I-10H (18)

I-10K (10)

I-10L (8)

Most of the I-10s were scrapped during the 1920s, although about a third (40) of the class survived into the early 1930s.


Class I-100a (Locobase 5351)

Data from table in July 1904 AERJ and P&LE 1 - 1908 Locomotive Diagrams supplied in August 1913 by Allen Stanley from his extensive Rail Data Exchange collection. Works numbers were 26337-26341 in 1903.

Firebox heating surface includes 24.41 sq ft (2.27 sq m) of arch tubes and relatively small drivers for an Atlantic. The class was later superheated -- see Locobase 6764.


Class I-100a - superheated (Locobase 6764)

Data from P&LE-PMcK&Y 3 - 1926 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Wes Barris of steamlocomotive.com for his 5 June 2018 email noting an out-of-whack driver diameter.)

When the P&E's Atlantics (Locobase 5351) were superheated, it resulted in the usual tradeoff of overall heating surface decreasing, but effective heating surface increasing. At the same time, it appears that the NYC removed the arch tubes from the firebox, which reduced direct heating surface. The result was something of a wash in terms of power and steam supply at speed, Locobase supposes. Other changes were the installation of piston valves actuated by outside radial valve gear.

Thicker tires later increased driver diameter by an inch to 73" (1,854 mm).


Class I-2 (Locobase 108)

The data comes from a reproduction of the New York Central's 1902 Locomotive guide found on [] (visited December 2002). (Many thanks to Chris Hohl for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error .) Works numbers were 6128, 6136-6137 in early 1901, not long before Schenectady joined with several other builders to create the American Locomotive Company.

Staufer (New York Central's Early Power, 1967) says that this trio "pretty well sum up the locomotive philosophy of this railroad [the StL&A]-- the latest, best and fanciest." Like other Atlantics, they could be slippery, so the design included a "traction increaser" that transferred 3,700 lb (1,678 kg) of weight from the trailing truck to the drivers.

Later renumberings put the lead engine at 2800, then 3800, and finally at 800.


Class I-3 (Locobase 5384)

Data from "Balanced Compound for the New York Central", Railway Age, Volume 38, (31 March 1905), p. 538-539. See also DeGolyer, Volume 27, p. 300. Works number was 25000 in January 1905.

The record shows this to have been the Baldwin balanced compound counterpart of a Schenectady-built Cole balanced compound (Locobase 4092) tested by the railroad against reigning I-class simple-expansion Atlantic designs such as Locobase 5292. Unlike the Cole-design balanced compound described in some detail in Locobase 389, which put the inside HP cylinders ahead of the outside LP cylinders, Baldwin's four cylinders were arranged in battery (side by side by side by side) with each of two 15" (381 mm) piston valves (1" greater diameter than the Cole valves) set above each side's LP and HP cylinders. The two pistons on each side's cylinders moved in opposite directions at the same time, which contributed to the reduction of dynamic loads and smoothed the motion.

Baldwin used fewer, but larger and longer firetubes in a boiler that offered about 200 sq ft (18.58 sq m) more evaporative heating surface area. Firebox heating surface area included 23 sq ft (2.14 sq m) of firebrick (arch) tubes. A Coffin Mageath Supply "smoke consumer" was installed and asbestos was lagged in every cranny of the complex cylinder bundles.

The Central ended the experiment very soon after it began and ordered dozens more simple-expansion locomotives. It scrapped this lone Baldwin and its Alco counterpart in November 1913


Class I-40a (Locobase 5548)

The data comes from a reproduction of the New York Central's 1930 Locomotive guide found on [] (visited May 2003). Works numbers were 40532-40541 in January 1907.

Data from NYC 8 - 1917 Locomotive Diagram book (supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange) surprised Locobase because it showed these Atlantics to have been superheated by August 1917. The viewer can see what the locomotives looked like in their short time as saturated engines on Locobase 7339, which profiles five identical locomotives supplied to the Ann Arbor in the same year.

Half of the class was scrapped in the early 30s. Five--4752-4753, 4755, 4758-4759--were renumbered 4320-4324 in 1936. The last two went to the scrapper in early 1939 and the 4320 followed in September 1940. But 4321-4322 remained on the roster through World War II before succumbing to the ferro-knacker's instruments in July 1947.


Class I-60 (Locobase 6685)

Data from the CCC&StL 3 - 1914 Locomotive Diagrams, supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange collection, . See also R A S Hennessey, Atlantic: The Well-Beloved Engine (Stroud, Gloucestershire: Tempus Publishing Co, Ltd, 2002).

Interesting anomaly of a quartet of Atlantics that the Big Four did not superheat (at least not by 1914). They had a generous amount of heating surface, and perhaps the trend toward hotting up the 4-4-2 had passed on the New York Central system.

The entire class traveled to Central subsidiary Peoria & Eastern in March 1917. The first of the foursome retired in November 1927, the last in December 1930.


Class I-61, I-62, I-63 (Locobase 6687)

Data from the CCC&StL 3 - 1914 Locomotive Diagrams, supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange and "Simple Atlantic Type Locomotive, C, C, C & St L Ry", Railroad Exhibits, Louisiana Purchase Exposition, Railway & Engineering Review, Special Issue (31 December 1904), p 108. See also R A S Hennessey, Atlantic: The Well-Beloved Engine (Stroud, Gloucestershire: Tempus Publishing Co, Ltd, 2002). Works numbers were 25504-25511 in August 1902, 25512-25513 in September 1902; 27961-27962, 28265-28274 in August 1903; 28411 in March 1904, and 29736-29745 in May.

Roger Hennessey noted that a design driving piston valves (in this case, 11" in (279 mm) diameter with 5 9/16"/141 mm travel) with inside Stephenson link motion was a trademark of Brooks's Atlantics. According to then-prevailing opinion, the boiler's 2" fire tubes' 16 foot (4.88 m) length came close to the ideal 100:1 ratio.

They were obvious successors to the eight-wheelers put into service on the Big Four's expresses just a few years earlier. They offered little more power, but with the substantially bigger boiler and grate, were probably able sustain that power for much longer with a much heavier train.

All three subclasses were later superheated; see Locobase 4097 for I-61, 6686 for the I-62, 10758 for the I-63.


Class I-61-superheated (Locobase 4097)

Taken from a table in Paul T Warner's article on Atlantics in the Railway & Locomotive Historical Society Bulletin #62 (1943, p 20). Additional data from the CCC&StL 3 - 1914 Locomotive Diagrams, supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

When the Big Four superheated this class, seven of the ten retained their link motion. 6909, 6911, and 6913 received Walschaert's outside radial valve gear. Arch tubes were installed in all fireboxes; they increased direct heating surface area by 20 sq ft (1.86 sq m).


Class I-62 superheated (Locobase 6686)

Data from the CCC&StL 3 - 1914 Locomotive Diagrams, supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Most of the Big Four's Atlantics were superheated using a common boiler. The I-62/I-62A/I-63s had smaller grates than other classes. I-62/I-62A engines differed from I-63s in the choice of valve gear in that all I-62 series engines retained their Stephenson link motion after superheating.

Some time after their makeovers, three of the engines--6915-6916 and 6918--went to the Central's subsidiary Peoria & Eastern in May 1922.


Class I-63 superheated (Locobase 10758)

Data from the CCC&StL 3 - 1914 Locomotive Diagrams, supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

For four of the class, only a slightly higher weight and slightly less firebox heating surface area distinguished the superheated version of the I-63 from that of the I-62 (Locobase 6686). The other four--6930, 6932, 6934, 6939--were refitted with outside radial valve gear.


Class I-j-superheated (Locobase 6684)

Data from the CCC&StL 3 - 1914 Locomotive Diagrams, supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

These superheated Atlantics show the usual tradeoffs in such an upgrade. By later standards, the amount of superheat is relatively modest and total heating surface area has actually decreased. Still, the steam was drier and total available power increased.

By 1914, 6949-6950 had been fitted with Walschaert gear and 6945 used Baker gear. Most had received arch tubes in the firebox which contributed 27 sq ft (2.51 sq m) to the 202 sq ft of direct heating surface. 6954-6956 were transferred to the Central's Peoria & Eastern in June 1924 (6955-6956) and August (6954). All three were retired in 1934.


Class Ib (Locobase 15834)

Data from NYC&HR 9-1905 Locomotive Diagram supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange. See also "Railway News and Gossip", Indian Engineering, Volume 34 (15 August 1903), p. 111. Works numbers were 25296-25301 in June 1902.

Patrick Doyle, IE's editor, noted that the firebox heating surface area included 27.09 sq ft (2.52 sq m) in water tubes.


Class Ic (Locobase 5294)

The data comes from a reproduction of the New York Central's 1902 Locomotive guide found on [] (visited December 2002). Works numbers were 27873-27879 in 1903.

Similar to the I and Ia classes, but with a slightly smaller boiler and fewer firetubes. According to the guide, these classes were fitted with traction increasers that increased the weight on the drivers by 10,000 lb. Engine weight was redistributed from the leading and trailing trucks.


Class Id/I-10d (Locobase 15863)

Data from NYC&HR 9-1905 Locomotive Diagrams Including Subsidiaries supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 29580-29582 in April 1904 and 29583-29598 in May.

The class used 12" (305 mm) piston valves to supply steam to the cylinders.


Class Ie (Locobase 15864)

Data from NYC&HR 9-1905 Locomotive Diagrams Including Subsidiaries supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange. Works number was 29599 in May 1905.

The last in a batch of Atlantics described in Locobase 15863 was among the first locomotives in North America to be delivered with some kind of superheater. The Cole superheater was essentially a variation on Schmidt's fire tube superheater.

The 915 was the only engine in its class and remained in service until 1923.


Class If/I-10f (Locobase 15865)

Data from the NYC&HR 9-1905 Locomotive Diagrams Including Subsidiaries supplied in May 2013 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 37838-37857 in 1906 and 38711-38730 in 1907.

The last of the Big Four's Atlantics, these continued the basic pattern of the railroad's express engines. Their cylinders received their steam through 12" (305 mm) piston valves.

Like the others, these were superheated not very long after their introduction.


Class Ij (Locobase 6683)

Data from the CCC&StL 3 - 1914 Locomotive Diagrams, supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 41381-41400 in 1906-1907.

The last of the Big Four's Atlantics, these continued the basic pattern of the railroad's express engines. Like the others, these were superheated not very long after their introduction. See Locobase 6684.


Class K/I-80 (Locobase 11473)

Data from "New Locomotive Equipment," The Railway Age, Vol XXXI, No 2 (25 January 1901), p 75, corrected by "New Michigan Central Locomotives," The Railway Age, Vol XXXII, No 2 (12 July 1901), pp. 25-26. (Many thanks to Chris Hohl for his extensive 29 January 2015 email detailing the I-80s on the Michigan Central and Canada Southern.) Works numbers were 6056, 6059 in June, 25887-25892 in March 1902, 25893 in May, 26835-26840 in November.

This class of Atlantics was very similar to the New York Central's I-class locomotives (Locobase 5293), but with a few more boiler tubes. Schenectady delivered six in 1901, ten in 1902. The slipperiness and relatively low ratio of weight on the drivers undoubtedly informed the installation of a "traction increaser" used by the engineer to shift 15,000 lb (6,804 kg) more of the engine weight onto the drivers. The tender used a drop-down water scoop to pick up water from troughs as the train rolled along.

The July report was able to supply more accurate information as well as giving the usual glowing report of their performance: "The engines are giving very good satisfaction since their delivery, one of them on the Canada division having hauled train No. 31. consisting of nine cars, from Saint Thomas to Windsor, 111 miles, in 102 minutes." Exhibits presented in a dispute between the MC and the State of Michigan included the price of the two 1902 batches: $15,200 each for the first three, $16,500 for the last seven.

All but one of the class remained with the MC until their retirements. The exception was 8085, which went to work for the Detroit, Toledo & Ironton as their 44.


Class K/I-80 (Locobase 15964)

Data from "New Locomotive Equipment," The Railway Age, Vol XXXI, No 2 (25 January 1901), p 75, corrected by "New Michigan Central Locomotives," The Railway Age, Vol XXXII, No 2 (12 July 1901), pp. 25-26. (Many thanks to Chris Hohl for his extensive 29 January 2015 email detailing the I-80s on the Michigan Central and Canada Southern.) Works numbers were 6054-6055, 6057-6058 in June 1901, 25894-25895 in March 1902, 25893 in May, 26841-26844 in November.

This set of ten Atlantics rolled down the production line both before and after those of the Michigan Central shown in Locobase 11473. Exhibits presented in a dispute between the MC and the State of Michigan included the price of the two 1902 batches: $15,200 each for the first four, $16,500 for the last two.

As with the Michigan Central batches, the slipperiness and relatively low ratio of weight on the drivers undoubtedly informed the installation of a "traction increaser" used by the engineer to shift 15,000 lb (6,804 kg) more of the engine weight onto the drivers. The tender used a drop-down water scoop to pick up water from troughs as the train rolled along.

All but one of the class remained with the CASO until their retirements. The exception was 8077, which went to work for the Detroit, Toledo & Ironton as their 45.

Principal Dimensions by Steve Llanso of Sweat House Media
ClassI - 20 1/2""//IaI - 21 1/2""/I-10I-1I-10I-100a
Locobase ID5292 5293 4092 5547 5351
RailroadNew York Central (NYC)New York Central (NYC)New York Central (NYC)New York Central (NYC)Pittsburgh & Lake Erie (NYC)
CountryUSAUSAUSAUSAUSA
Whyte4-4-24-4-24-4-24-4-24-4-2
Number in Class522011345
Road Numbers2658+/2923-29472954-2968/3954-3968/954-9683000/3803/803782-990 (broken series)301-305/9200-9204
GaugeStdStdStdStdStd
Number Built522015
BuilderSchenectadySchenectadyAlco-SchenectadySchenectadyAlco-Schenectady
Year19011901190419121903
Valve GearStephensonStephensonWalschaertBakerStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)7 / 2.137 / 2.137 / 2.137 / 2.137 / 2.13
Engine Wheelbase (ft / m)27.25 / 8.3127.25 / 8.3127.75 / 8.4627.42 / 8.3626.83 / 8.18
Ratio of driving wheelbase to overall engine wheebase 0.26 0.26 0.25 0.26 0.26
Overall Wheelbase (engine & tender) (ft / m)53 / 16.1553 / 16.1553.67 / 16.3659.04 / 1857.17 / 17.43
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)104,800 / 47,537104,800 / 47,537110,000 / 49,895109,000 / 49,44298,000 / 44,452
Engine Weight (lbs / kg)176,000 / 79,832176,000 / 79,832200,000 / 90,719196,000 / 88,904188,000 / 85,275
Tender Loaded Weight (lbs / kg)114,000 / 51,710114,000 / 51,710124,000 / 56,246130,000 / 58,967145,000 / 65,771
Total Engine and Tender Weight (lbs / kg)290,000 / 131,542290,000 / 131,542324,000 / 146,965326,000 / 147,871333,000 / 151,046
Tender Water Capacity (gals / ML)5000 / 18.945000 / 18.946000 / 22.736000 / 22.738400 / 31.82
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)10 / 9.1010 / 9.1010 / 9.1010 / 9.1010 / 9.10
Minimum weight of rail (calculated) (lb/yd / kg/m)87 / 43.5087 / 43.5092 / 4691 / 45.5082 / 41
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)79 / 200779 / 200779 / 200779 / 200772 / 1829
Boiler Pressure (psi / kPa)200 / 13.80200 / 13.80220 / 15.20180 / 12.40200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)20.5" x 26" / 521x66021.5" x 26" / 533x66015.5" x 26" / 394x66021.5" x 26" / 546x66020" x 26" / 508x660
Low Pressure Cylinders (dia x stroke) (in / mm)26" x 26" / 660x660
Tractive Effort (lbs / kg)23,513 / 10665.3325,863 / 11731.2721,818 / 9896.4923,276 / 10557.8324,556 / 11138.43
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.46 4.05 5.04 4.68 3.99
Heating Ability
Firebox Area (sq ft / m2)180 / 16.73207.09 / 19.25198 / 18.39194 / 18.03191.26 / 17.77
Grate Area (sq ft / m2)50.32 / 4.6850.32 / 4.6850.30 / 4.6750.20 / 4.6746.27 / 4.30
Evaporative Heating Surface (sq ft / m2)3505 / 325.743505 / 325.743446 / 320.142561 / 238.012941 / 273.23
Superheating Surface (sq ft / m2)510 / 47.40
Combined Heating Surface (sq ft / m2)3505 / 325.743505 / 325.743446 / 320.143071 / 285.412941 / 273.23
Evaporative Heating Surface/Cylinder Volume352.88320.82606.88234.41311.09
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation10,06410,06411,06690369254
Same as above plus superheater percentage10,06410,06411,06610,5729254
Same as above but substitute firebox area for grate area36,00041,41843,56040,85638,252
Power L111,67910,944804317,6179894
Power MT491.37460.45322.40712.64445.15

Principal Dimensions by Steve Llanso of Sweat House Media
ClassI-100a - superheatedI-2I-3I-40aI-60
Locobase ID6764 108 5384 5548 6685
RailroadPittsburgh & Lake Erie (NYC)St Lawrence & Adirondack (NYC)New York Central (NYC)Lake Shore & Michigan Southern (NYC)Big Four (NYC)
CountryUSAUSAUSAUSAUSA
Whyte4-4-24-4-24-4-24-4-24-4-2
Number in Class531104
Road Numbers9200-920410-12/2900-29023804/8044750-4759/ 4320-43246900-6903
GaugeStdStdStdStdStd
Number Built31104
BuilderAlco-SchenectadyAlco-SchenectadyBurnham, Williams & CoAlco-SchenectadySchenectady
Year19171901190519071901
Valve GearBakerStephensonStephensonWalschaertStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)7 / 2.137 / 2.137 / 2.137 / 2.138 / 2.44
Engine Wheelbase (ft / m)26.83 / 8.1826.92 / 8.2130.75 / 9.3725.96 / 7.9121.92 / 6.68
Ratio of driving wheelbase to overall engine wheebase 0.26 0.26 0.23 0.27 0.36
Overall Wheelbase (engine & tender) (ft / m)57.26 / 17.4557.08 / 17.4056.67 / 17.2758.47 / 17.8259.29 / 18.07
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)106,000 / 48,08198,550 / 44,702110,000 / 49,89595,800 / 43,45494,000 / 42,638
Engine Weight (lbs / kg)186,800 / 84,731168,000 / 76,204204,500 / 92,760167,500 / 75,977173,000 / 78,472
Tender Loaded Weight (lbs / kg)145,000 / 65,771120,700 / 54,749124,000 / 56,246151,900 / 68,901151,000 / 68,493
Total Engine and Tender Weight (lbs / kg)331,800 / 150,502288,700 / 130,953328,500 / 149,006319,400 / 144,878324,000 / 146,965
Tender Water Capacity (gals / ML)8400 / 31.825900 / 22.356000 / 22.737500 / 28.417500 / 28.41
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)10 / 9.1010 / 9.1010 / 9.1014 / 12.7012 / 10.90
Minimum weight of rail (calculated) (lb/yd / kg/m)88 / 4482 / 4192 / 4680 / 4078 / 39
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)72 / 185469 / 175379 / 200769 / 175379 / 2007
Boiler Pressure (psi / kPa)200 / 13.80200 / 13.80225 / 15.50180 / 12.40200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)20" x 26" / 508x66019" x 26" / 483x66015.5" x 26" / 394x66019" x 26" / 483x66020" x 26" / 508x660
Low Pressure Cylinders (dia x stroke) (in / mm)26" x 26" / 660x660
Tractive Effort (lbs / kg)24,556 / 11138.4323,125 / 10489.3422,314 / 10121.4720,812 / 9440.1822,380 / 10151.41
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.32 4.26 4.93 4.60 4.20
Heating Ability
Firebox Area (sq ft / m2)166.90 / 15.51184.37 / 17.13168.80 / 15.68151.60 / 14.09202 / 18.77
Grate Area (sq ft / m2)46.27 / 4.3046.58 / 4.3350.30 / 4.6739.20 / 3.6450.20 / 4.67
Evaporative Heating Surface (sq ft / m2)2170 / 201.673016 / 280.303628 / 337.051850 / 171.933470 / 322.49
Superheating Surface (sq ft / m2)462 / 42.94357 / 33.18
Combined Heating Surface (sq ft / m2)2632 / 244.613016 / 280.303628 / 337.052207 / 205.113470 / 322.49
Evaporative Heating Surface/Cylinder Volume229.54353.49638.93216.83367.05
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation9254931611,318705610,040
Same as above plus superheater percentage10,920931611,318818510,040
Same as above but substitute firebox area for grate area39,38836,87437,98031,65440,400
Power L118,18310,615829214,12212,479
Power MT756.35474.93332.38649.97585.35

Principal Dimensions by Steve Llanso of Sweat House Media
ClassI-61, I-62, I-63I-61-superheatedI-62 superheatedI-63 superheatedI-j-superheated
Locobase ID6687 4097 6686 10,758 6684
RailroadBig Four (NYC)Big Four (NYC)Big Four (NYC)Big Four (NYC)Big Four (NYC)
CountryUSAUSAUSAUSAUSA
Whyte4-4-24-4-24-4-24-4-24-4-2
Number in Class2626161020
Road Numbers386-395, 374-385, 373, 363-372/6904-69396914-6929, 6930-396914-69296330-63396940-6959
GaugeStdStdStdStdStd
Number Built26
BuilderBrooksShopsShopsShopsShops
Year19021914191419141906
Valve GearStephensonStephenson or WalschStephensonStephenson or WalschWalschaert or Baker
Locomotive Length and Weight
Driver Wheelbase (ft / m) 7.50 / 2.29 7.50 / 2.29 7.50 / 2.29 7.50 / 2.297 / 2.13
Engine Wheelbase (ft / m)22.58 / 6.8822.58 / 6.8822.58 / 6.8822.58 / 6.8821.83 / 6.65
Ratio of driving wheelbase to overall engine wheebase 0.33 0.33 0.33 0.33 0.32
Overall Wheelbase (engine & tender) (ft / m)56.61 / 17.2559.45 / 18.1259.25 / 18.0659.25 / 18.0659.04 / 18
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)104,000 / 47,174100,000 / 45,359100,000 / 45,359104,000 / 47,174105,500 / 47,854
Engine Weight (lbs / kg)186,000 / 84,368186,000 / 84,368186,000 / 84,368186,000 / 84,368188,100 / 85,321
Tender Loaded Weight (lbs / kg)151,000 / 68,493151,000 / 68,493151,000 / 68,493151,000 / 68,493150,500 / 68,266
Total Engine and Tender Weight (lbs / kg)337,000 / 152,861337,000 / 152,861337,000 / 152,861337,000 / 152,861338,600 / 153,587
Tender Water Capacity (gals / ML)7500 / 28.417500 / 28.417500 / 28.417500 / 28.417500 / 28.41
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)10 / 9.1012 / 10.9012 / 10.9012 / 10.9012 / 10.90
Minimum weight of rail (calculated) (lb/yd / kg/m)87 / 43.5083 / 41.5083 / 41.5087 / 43.5088 / 44
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)79 / 200779 / 200779 / 200779 / 200779 / 2007
Boiler Pressure (psi / kPa)200 / 13.80200 / 13.80200 / 13.80200 / 13.80200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)20" x 26" / 508x66020.5" x 26" / 521x66020.5" x 26" / 521x66020.5" x 26" / 521x66021" x 26" / 533x660
Tractive Effort (lbs / kg)22,380 / 10151.4123,513 / 10665.3323,513 / 10665.3323,513 / 10665.3324,674 / 11191.95
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.65 4.25 4.25 4.42 4.28
Heating Ability
Firebox Area (sq ft / m2)181 / 16.82209 / 19.42194 / 18.03194 / 18.03202 / 18.77
Grate Area (sq ft / m2)44.80 / 4.1650.20 / 4.6744.80 / 4.1644.80 / 4.1650.20 / 4.67
Evaporative Heating Surface (sq ft / m2)3196 / 296.922461 / 228.722454 / 228.072454 / 228.072437 / 226.49
Superheating Surface (sq ft / m2)498 / 46.28498 / 46.28498 / 46.28493 / 45.82
Combined Heating Surface (sq ft / m2)3196 / 296.922959 / 2752952 / 274.352952 / 274.352930 / 272.31
Evaporative Heating Surface/Cylinder Volume338.06247.77247.07247.07233.81
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation896010,0408960896010,040
Same as above plus superheater percentage896011,74710,48310,48311,747
Same as above but substitute firebox area for grate area36,20048,90645,39645,39647,268
Power L111,42321,17820,96120,96119,919
Power MT484.30933.79924.22888.67832.49

Principal Dimensions by Steve Llanso of Sweat House Media
ClassIbIcId/I-10dIeIf/I-10f
Locobase ID15,834 5294 15,863 15,864 15,865
RailroadBoston & Albany (NYC)New York Central (NYC)New York Central (NYC)New York Central (NYC)Big Four (NYC)
CountryUSAUSAUSAUSAUSA
Whyte4-4-24-4-24-4-24-4-24-4-2
Number in Class6719140
Road Numbers2948-2953/3948-39532916-2922/3916-3922/916-9222896-2914/3896-3914/896-9142915/3915/9153876-3895, 3856-3875/876-895, 856-875
GaugeStdStdStdStdStd
Number Built6719140
BuilderAlco-SchenectadySchenectadySchenectadySchenectadyAlco-Schenectady
Year19021903190419041906
Valve GearStephensonStephensonStephensonStephensonStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)7 / 2.137 / 2.137 / 2.137 / 2.137 / 2.13
Engine Wheelbase (ft / m)27.25 / 8.3127.50 / 8.3827.50 / 8.3827.50 / 8.3827.58 / 8.41
Ratio of driving wheelbase to overall engine wheebase 0.26 0.25 0.25 0.25 0.25
Overall Wheelbase (engine & tender) (ft / m)53 / 16.1553.42 / 16.2853.42 / 16.2853.42 / 16.2859.75 / 18.21
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)104,800 / 47,537104,800 / 47,537102,000 / 46,266102,000 / 46,266105,000 / 47,627
Engine Weight (lbs / kg)176,000 / 79,832176,000 / 79,832186,000 / 84,368186,000 / 84,368190,000 / 86,183
Tender Loaded Weight (lbs / kg)114,000 / 51,710124,000 / 56,246124,000 / 56,246124,000 / 56,246122,000 / 55,338
Total Engine and Tender Weight (lbs / kg)290,000 / 131,542300,000 / 136,078310,000 / 140,614310,000 / 140,614312,000 / 141,521
Tender Water Capacity (gals / ML)5000 / 18.945000 / 18.946000 / 22.736000 / 22.736000 / 22.73
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)10 / 9.1010 / 9.1010 / 9.1010 / 9.1010 / 9.10
Minimum weight of rail (calculated) (lb/yd / kg/m)87 / 43.5087 / 43.5085 / 42.5085 / 42.5088 / 44
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)79 / 200779 / 200779 / 200779 / 200779 / 2007
Boiler Pressure (psi / kPa)200 / 13.80200 / 13.80200 / 13.80200 / 13.80200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)20.5" x 26" / 521x66020.5" x 26" / 521x66020.5" x 26" / 521x66020.5" x 26" / 521x66021.5" x 26" / 546x660
Tractive Effort (lbs / kg)23,513 / 10665.3323,513 / 10665.3323,513 / 10665.3323,513 / 10665.3325,863 / 11731.27
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.46 4.46 4.34 4.34 4.06
Heating Ability
Firebox Area (sq ft / m2)180 / 16.73180 / 16.72180 / 16.72180 / 16.72194 / 18.02
Grate Area (sq ft / m2)50.32 / 4.6850.32 / 4.6750.32 / 4.6750.32 / 4.6750.20 / 4.66
Evaporative Heating Surface (sq ft / m2)3505 / 325.743455 / 320.983406 / 316.433016 / 280.193355 / 311.69
Superheating Surface (sq ft / m2)574 / 53.33
Combined Heating Surface (sq ft / m2)3505 / 325.743455 / 320.983406 / 316.433590 / 333.523355 / 311.69
Evaporative Heating Surface/Cylinder Volume352.88347.85342.92303.65307.09
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation10,06410,06410,06410,06410,040
Same as above plus superheater percentage10,06410,06410,06411,67410,040
Same as above but substitute firebox area for grate area36,00036,00036,00041,76038,800
Power L111,67911,54611,41624,07910,425
Power MT491.37485.77493.491040.88437.77

Principal Dimensions by Steve Llanso of Sweat House Media
ClassIjK/I-80K/I-80
Locobase ID6683 11,473 15,964
RailroadBig Four (NYC)Michigan Central (NYC)Canada Southern (NYC)
CountryUSAUSAUSA
Whyte4-4-24-4-24-4-2
Number in Class201610
Road Numbers6940-6959251-266/7950-7965/8082-8097480-489/7910-7919/8072-8081
GaugeStdStdStd
Number Built201610
BuilderAlco-SchenectadySchenectadySchenectady
Year190619011901
Valve GearStephensonStephensonStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)7 / 2.137 / 2.137 / 2.13
Engine Wheelbase (ft / m)21.83 / 6.6527.25 / 8.3127.25 / 8.31
Ratio of driving wheelbase to overall engine wheebase 0.32 0.26 0.26
Overall Wheelbase (engine & tender) (ft / m)59.04 / 1855.18 / 16.8255.18 / 16.82
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)105,500 / 47,85495,000 / 43,09195,000 / 43,091
Engine Weight (lbs / kg)188,100 / 85,321176,000 / 79,832176,000 / 79,832
Tender Loaded Weight (lbs / kg)150,500 / 68,266
Total Engine and Tender Weight (lbs / kg)338,600 / 153,587
Tender Water Capacity (gals / ML)7500 / 28.416000 / 22.736000 / 22.73
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)12 / 10.9014 / 12.7014 / 12.70
Minimum weight of rail (calculated) (lb/yd / kg/m)88 / 4479 / 39.5079 / 39.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)79 / 200779 / 200779 / 2007
Boiler Pressure (psi / kPa)200 / 13.80200 / 13.80200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)21" x 26" / 533x66021" x 26" / 533x66021" x 26" / 533x660
Tractive Effort (lbs / kg)24,674 / 11191.9524,674 / 11191.9524,674 / 11191.95
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.28 3.85 3.85
Heating Ability
Firebox Area (sq ft / m2)202 / 18.77207.09 / 19.24207.09 / 19.24
Grate Area (sq ft / m2)50.20 / 4.6750.30 / 4.6750.30 / 4.67
Evaporative Heating Surface (sq ft / m2)3295 / 306.233505 / 325.623505 / 325.62
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)3295 / 306.233505 / 325.623505 / 325.62
Evaporative Heating Surface/Cylinder Volume316.13336.28336.28
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation10,04010,06010,060
Same as above plus superheater percentage10,04010,06010,060
Same as above but substitute firebox area for grate area40,40041,41841,418
Power L110,87711,47111,471
Power MT454.59532.40532.40

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