New York, New Haven & Hartford 4-6-2 "Pacific" Locomotives in the USA

The first nine New York, New Haven & Hartford "Pacifics" were delivered from the American Locomotive Company's Schenectady Works in September 1907. These locomotives were designated as Class I-1 and were given road numbers 1000 through 1008. They had 22 x 28 cylinders, 73" drivers, a 200 psi boiler pressure, exerted 31,600 lbs of tractive effort and each weighed 229,500 pounds. In September and October of 1907, the Baldwin Locomotive Works delivered 21 more Class I-1 which were very similar to the ALCO locomotives and they were given road numbers 1009 through 1029. A final pair of Class I-1 locomotives (road numbers 1030 and 1031) arrived from ALCO in 1910 and were very similar to the earlier ones. Between 1912 and 1923 all 32 of the Class I-1 locomotives were reworked. The cylinders were enlarged to 23" diameter, superheaters were added and the total weight was increased to 234,400 pounds. The change in the cylinder diameter increased the tractive effort to 34,493 lbs.

In just a few years the length and weight of passenger trains were increasing and the I-1 "Pacifics" were having difficulty keeping up. So the NYNH&H designed and ordered new "Pacific" with more power. Fifty of the new Class I-2 came from ALCO in May and June of 1913. These locomotives (road numbers 1300 through 1349) had 24 x 28 cylinders, a larger boiler, but the same 73" diameter drivers as the I-1s. These new Class I-2 "Pacifics" could exert 37,558 lbs of tractive effort.

There were six other new "Pacifics" added to the roster in 1913. They were built by the Baldwin Locomotive Works, designated as Class I-3 and assigned road numbers 1090 through 1095. These locomotives had 24 x 28 cylinders, 79" drivers, a 200 psi boiler pressure, exerted 34,705 lbs of tractive effort and each weighed 246,000 pounds.

The last group of NYNH&H "Pacifics" were the fifty Class I-4 locomotives delivered by ALCO's Schenectady Works in 1916. These locomotives were assigned road numbers 1350 through 1399 and were designed to pull the heaviest passenger trains without double heading. They had 26 x 28 cylinders, 79" drivers, a 200 psi boiler pressure, exerted 40,731 lbs of tractive effort and each weighed 266.000 pounds. The I-4s were the top passenger locomotives on the NYNH&H for more than 20 years from 1916 until the mid 1930s.

Most of the NYNH&H "Pacifics" were used continuously through World War II, but were all retiired by 1952. There are no surviving examples of these locomotives.


Roster

ClassQty.Road NumbersYear BuiltBuilder
I-191000-10081907ALCO
211009-10291907Baldwin
21030 & 10311910ALCO
I-2501300-13491913ALCO
I-361090-10951913Baldwin
I-4501350-13991916ALCO

Class Details by Steve Llanso of Sweat House Media

Class I-1 (Locobase 157)

Data from table in June 1908 American Engineer and Railroad Journal (p. 230) and "New Passenger Locomotives for the New Haven", Railway Age, Volume 44 (27 December 1907), pp. 945-947. See also DeGolyer, Volume 29, pp. 250+. (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 .) Baldwin built 21 (works numbers 31681-31682, 31701, 31766-31770, 31813-31814, 31839 in September 1907; 31857-31858, 31874-31876, 31903, 31943-31944, 32008, 32058 in October) , Alco-Schenectady built 11 (works numbers were 41705-41713 in September 1907, 49094-49095 in November 1910.

Used on the Merchants, Bay State, and Knickerbocker Limiteds between New York and Boston in the first two decades of the 20th century; their mission was to bring the running time down to six hours. Although the adhesion weight remained about the same as the Ten-wheelers they were replacing, these engines had 55% more grate area to heat the boiler, which had almost 50% more heating surface area. Its firebox heating surface area included 29 sq ft (2.69 sq m) of "fire brick tubes" Pressed to 200 psi, the amount of available steam seems excessive for the cylinder volume specified, but RA points out that the large boiler was a deliberate choice

Slide valves were replaced in 1917 by piston valves, at which time superheaters were added; see Locobase 8116.


Class I-1-a (Locobase 8116)

Data from NH 1962 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Locobase 157 describes the first New Haven Pacific class as delivered in its saturated-boiler form. Beginning in 1917, the railroad began modifying these engines by installing a superheated boiler. The usual decrease in total heating surface induced by swapping many small tubes for a fewer larger flues was held to a relatively small figure. At the same time, the firebox gained some area with the addition of more arch tubes (the total impact on firebox heating surface now came to 29 sq ft) and the cylinders gained a little volume by growing an inch in diameter.

Interestingly, the 4-4-2 upgrade described in Locobase 8115 achieved almost the same power at speed because although the boiler was a bit smaller, the cylinders were smaller as well, which reduced demand. Moreover, the direct heating surface was little different. Total water evaporation was a bit higher in the 4-6-2 at 38,330 lb/hour, but the direct heating surface contributed only 11,045 lb/hour. Steam consumption could overmatch the boiler by achieving a theoretical 39,600 lb/hour; thus the boiler factor was 96.2%.

But of course the Pacific put more weight on the drivers and that proved a decisive advantage.

The superheat upgrade proved to be the last big change for the I-1s and they served the New Haven for decades more in that form. The first left service in 1944 and the last retired in 1951.


Class I-2 (Locobase 7590)

Data from reproduction of 1913 Alco Bulletin 1016 on Richard Leonard's [] (accessed 16 June 2006).

Drury (1993) says this class replaced the I-1s (Locobase 157) in mainline passenger service and also worked fast freights. Certainly it's a bigger locomotive with excellent proportions -- an adequate superheat ratio, large boiler, good factor of adhesion. Yet maximum water evaporation increased very little, up only 1,422 lb/hour to 39,752 lb/hour. Steam consumption grew at a faster rate, however, reaching 43,180 lb/hour and the boiler factor fell to 92.1%

Perhaps because of the lack of any real margin growth, the I-2s were overshadowed by the I-4s (Locobase 5465) that came on the road just 3 years later and relegated to secondary passenger traffic. In that role they served the line until the end of steam, being retired in 1948-1952.


Class I-3 (Locobase 9400)

Data from NH 1962 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 43, pp. 1+; and "Pacific Type Locomotives; New York, New Haven and Hartford, RR", Railway Engineer, Volume 34, No 6 (June 1913), pp. 181. Works numbers were 39173-39174 in January 1913, 39175-39178 in February 1913.

To work the express-passenger Shoreliner service, Baldwin superheated the 1907 I-1 design discussed in Locobase 157. In its 1913 form, the engine rolled on taller drivers, used even longer tubes in the boiler, and added a superheater. The latter prompted the replacement of the I-1's slide valves with 12" (305 mm) piston valves. Firebox heating surface area included 29 sq ft (2.69 sq m) of arch tubes.

Compared to its contemporary I-2 built by Alco's Brooks Works, the total maximum evaporation rates differed little, reaching 39,695 lb/hour. Maximum possible steam consumption remained 43,180 lb/hour. Adhesion weight in the Baldwins would later climb to 161,100 lb (73,074 kg) and engine weight to 259,000 lb (117,481 kg).

It's little wonder, therefore, that the Shoreline duties were quickly filled by the I-4s when they began entering service in 1916 (Locobase 5465). The I-3s were relegated to secondary pasenger runs, they nevertheless served until the late 1940s.


Class I-4 (Locobase 5465)

Data from table in January 1917 issue of Railway Mechanical Engineer (RME). Works numbers were 56104-56153 in September 1916.

Express Pacifics for the New York, New Haven & Hartford that headed the varnish between New York and Boston. For some very long trains (as many as 23 cars, e.g.), the New Haven would double up on I-4 power.

Compared to Brooks's I-2s (Locobase 7590), these engines had taller drivers and larger-diameter cylinders. RME shows the class as having 71 1/4 sq ft of grate area, but Locobase later ascertained through the NH 1962 Locomotive Diagram book (supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange) that this was mistaken. In later years, they were easily distinguished by the Elesco feedwater heater mounted athwart the smokebox and, more unusually, by the air tanks laid longitudinally on each upper half of the boiler just behind the stack.

Later on, the New Haven made over some number (Locobase isn't sure how many) into superpower engines; see Locobase 7591.


Class I-4-E (Locobase 12721)

Data from NH 1962 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

As noted in Locobase 7591, the New Haven met the burgeoning demand for heavy passenger trains led to upgrades of some of the I-4s to a superpower standard (see Locobase 7591). This entry reflects another subset that used the original boiler layout but added 3 thermic syphons of 91 sq ft and modernized the Baker valve gear by fitting it with roller bearings.

As in the more extensive makeover, boiler pressure remained the same, but the cylinders shrank by 1" in diameter. The tender was much bigger and heavier.

The New Haven calculated that the augmented boiler evaporated water at the maximum rate of 49,730 lb/hour, of which the direct heating surface contributed 20,130 lb/hour. Compared to the maximum steam consumption rate of 46,840 lb/hour, the boiler factor came to 106%.


Class I-4-F (Locobase 7591)

Data from NH 1962 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

When delivered in 1916, the I-4 class (Locobase 5465) was a pretty potent express locomotive design. But as trains grew longer and heavier still, the New Haven began double-heading them. To meet the demand, the railroad procured the famed I-5 4-6-4s (Locobase 187) and modified some of the I-4s beyond the modest updates that appeared on the I-4-E (Locobase 12721).

The I-4-F rose to a superpower standard. In the makeover, boiler pressure remained the same, but the cylinders shrank by 1" in diameter, the Baker gear now used roller bearings, and the firebox received 91 sq ft of thermic syphons added to the firebox and combustion chamber. The tender was much bigger and heavier.

The big change came in the boiler. A redesign of the layout added considerable evaporative heating surface in not only the new combination of 2 1/4" tubes and 3 1/2" flue. Altogether, the design added about 25% in heating surface to the original I-4 boiler.

The New Haven calculated that the new boiler evaporated water at the maximum rate of 51,180 lb/hour, of which the direct heating surface contributed 20,130 lb/hour. Compared to the maximum steam consumption rate, the boiler factor came to 109.2%.

Principal Dimensions by Steve Llanso of Sweat House Media

ClassI-1I-1-aI-2I-3I-4
Locobase ID157 8116 7590 9400 5465
RailroadNew York, New Haven & Hartford (NYNH&H)New York, New Haven & Hartford (NYNH&H)New York, New Haven & Hartford (NYNH&H)New York, New Haven & Hartford (NYNH&H)New York, New Haven & Hartford (NYNH&H)
CountryUSAUSAUSAUSAUSA
Whyte4-6-24-6-24-6-24-6-24-6-2
Number in Class323250650
Road Numbers1000-10311000-10311300-13491090-10951350-1399
GaugeStdStdStdStdStd
Number Built3250650
BuilderseveralNew HavenAlco-BrooksBaldwinAlco-Schenectady
Year19071917191319131916
Valve GearWalschaertWalschaertWalschaertWalschaertBaker
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.08 / 3.9913.08 / 3.9914.08 / 4.2914.08 / 4.2914.08 / 4.29
Engine Wheelbase (ft / m)33.45 / 10.2033.46 / 10.2034.46 / 10.5036.10 / 1136.10 / 11
Ratio of driving wheelbase to overall engine wheelbase 0.39 0.39 0.41 0.39 0.39
Overall Wheelbase (engine & tender) (ft / m)61.17 / 18.6461.17 / 18.6462.33 / 1966.77 / 20.3566.77 / 20.35
Axle Loading (Maximum Weight per Axle) (lbs / kg)46,400 / 21,04754,150 / 24,56260,700 / 27,533
Weight on Drivers (lbs / kg)142,500 / 64,637142,800 / 64,773154,000 / 69,853153,100 / 69,445165,000 / 74,843
Engine Weight (lbs / kg)229,500 / 104,100234,400 / 106,322251,500 / 114,079246,200 / 111,675266,000 / 120,656
Tender Loaded Weight (lbs / kg)134,000 / 60,781134,000 / 60,781132,600 / 60,146132,600 / 60,146154,000 / 69,853
Total Engine and Tender Weight (lbs / kg)363,500 / 164,881368,400 / 167,103384,100 / 174,225378,800 / 171,821420,000 / 190,509
Tender Water Capacity (gals / ML)6000 / 22.736000 / 22.736000 / 22.736000 / 22.737500 / 28.41
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)14 / 1314 / 1313 / 1213 / 1212 / 11
Minimum weight of rail (calculated) (lb/yd / kg/m)79 / 39.5079 / 39.5086 / 4385 / 42.5092 / 46
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)73 / 185473 / 185473 / 185479 / 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)22" x 28" / 559x71123" x 28" / 584x71124" x 28" / 610x71124" x 28" / 610x71126" x 28" / 660x711
Tractive Effort (lbs / kg)31,559 / 14314.9434,494 / 15646.2337,558 / 17036.0434,706 / 15742.4040,731 / 18475.29
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.52 4.14 4.10 4.41 4.05
Heating Ability
Tubes (number - dia) (in / mm)310 - 2.25" / 57174 - 2.25" / 57179 - 2.25" / 57180 - 2.25" / 57198 - 2.25" / 57
Flues (number - dia) (in / mm)28 - 5.5" / 14032 - 5.5" / 14028 - 5.5" / 14036 - 5.5" / 140
Flue/Tube length (ft / m)20.50 / 6.2520.50 / 6.2520.50 / 6.2521.50 / 6.5518 / 5.49
Firebox Area (sq ft / m2)218.80 / 20.33219 / 20.35217 / 20.17223 / 20.72298 / 27.70
Grate Area (sq ft / m2)53.40 / 4.9653.50 / 4.9753.20 / 4.9453.50 / 4.9759.20 / 5.50
Evaporative Heating Surface (sq ft / m2)3944 / 366.413133 / 291.173309 / 307.533356 / 311.783315 / 308.09
Superheating Surface (sq ft / m2)670 / 62.27780 / 72.49730 / 67.82776 / 72.12
Combined Heating Surface (sq ft / m2)3944 / 366.413803 / 353.444089 / 380.024086 / 379.604091 / 380.21
Evaporative Heating Surface/Cylinder Volume320.13232.76225.72228.92192.62
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation10,68010,70010,64010,70011,840
Same as above plus superheater percentage10,68012,62612,66212,62614,090
Same as above but substitute firebox area for grate area43,76051,68451,64652,62870,924
Power L1995118,54518,94519,83318,039
Power MT461.86858.92813.63856.78723.08

Principal Dimensions by Steve Llanso of Sweat House Media

ClassI-4-EI-4-F
Locobase ID12721 7591
RailroadNew York, New Haven & Hartford (NYNH&H)New York, New Haven & Hartford (NYNH&H)
CountryUSAUSA
Whyte4-6-24-6-2
Number in Class1719
Road Numbers1350+1353+
GaugeStdStd
Number Built
BuilderNew HavenNew Haven
Year19301930
Valve GearBakerBaker
Locomotive Length and Weight
Driver Wheelbase (ft / m)14.08 / 4.2914.08 / 4.29
Engine Wheelbase (ft / m)36.10 / 1136.10 / 11
Ratio of driving wheelbase to overall engine wheelbase 0.39 0.39
Overall Wheelbase (engine & tender) (ft / m)79.92 / 24.3679.92 / 24.36
Axle Loading (Maximum Weight per Axle) (lbs / kg)60,300 / 27,35261,400 / 27,851
Weight on Drivers (lbs / kg)178,600 / 81,012180,800 / 82,010
Engine Weight (lbs / kg)287,500 / 130,408291,000 / 131,996
Tender Loaded Weight (lbs / kg)298,000 / 135,171298,000 / 135,171
Total Engine and Tender Weight (lbs / kg)585,500 / 265,579589,000 / 267,167
Tender Water Capacity (gals / ML)16,000 / 60.6116,000 / 60.61
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)16 / 1516 / 15
Minimum weight of rail (calculated) (lb/yd / kg/m)99 / 49.50100 / 50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)79 / 200779 / 2007
Boiler Pressure (psi / kPa)200 / 13.80200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)25" x 28" / 635x71125" x 28" / 635x711
Tractive Effort (lbs / kg)37,658 / 17081.4037,658 / 17081.40
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.74 4.80
Heating Ability
Tubes (number - dia) (in / mm)198 - 2.25" / 5754 - 2.25" / 57
Flues (number - dia) (in / mm)36 - 5.5" / 140160 - 3.5" / 89
Flue/Tube length (ft / m)18 / 5.4918 / 5.49
Firebox Area (sq ft / m2)366 / 34.01366 / 34.01
Grate Area (sq ft / m2)59.20 / 5.5059.20 / 5.50
Evaporative Heating Surface (sq ft / m2)3383 / 314.413576 / 332.34
Superheating Surface (sq ft / m2)776 / 72.121425 / 132.43
Combined Heating Surface (sq ft / m2)4159 / 386.535001 / 464.77
Evaporative Heating Surface/Cylinder Volume212.63224.76
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation11,84011,840
Same as above plus superheater percentage14,09015,155
Same as above but substitute firebox area for grate area87,10893,696
Power L120,18830,175
Power MT747.601103.83

  • 1029 (I-1 at Boston 5/15/47, photographer unknown courtesy Carl Weber)
  • 1091 (I-3 at Norwood, MA 06/1937, photographer unknown courtesy Carl Weber)
  • 1335 (I-2 at Boston 9/21/50, photographer unknown courtesy Carl Weber)
  • 1357 (I-4 at Providence 4/26/49, photographer unknown courtesy Carl Weber)
  • 1396 (I-4 at South Boston 5/17/51, Don Hayward photo courtesy Carl Weber)
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