D&RGW 2-6-6-2

[kgbw49]

BEAUSABRE, you are definitely on to something there! To borrow a phrase from the Guinness commercials, "Brilliant!"

Those NG 2-6-6-2s look like a "Mini Me"  version of the standard gauge L-131 and L-132 2-8-8-2s.

 

https://digital.denverlibrary.org/digital/collection/p15330coll22/id/49326/

https://www.trains.com/ctr/photos-videos/photo-of-the-day/rio-grande-2-8-8-2-on-tennessee-pass/

 

 

[BEAUSABRE]

They might well have resembled NdeM's 3 foot gauge Class HR-01 2-6-6-2's of the late 20's. They were modern articulateds - simple rather than compound, front end throttle, outside bearing leading truck. The roller skate sized wheels on the rear truck are probably because they are not there to support a big firebox, but guide the locomotive on reverse moves. Later they got Elesco feed water heaters, which, coupled with their smoke box front air compressors led Robert LeMassena to comment that they looked like what the C&O would have had if it had a narrow  gauge division. 

"The ultimate in North American narrow-gauge steam power was a group of 10 simple-expansion 2-6-6-2s built by Alco for NdeM during 1929–37. In March 1948, No. 369 backs onto a passenger train at Mexico City’s Buenavista Station."

(2) Pinterest

Principal Dimensions by Steve Llanso of Sweat House Media
Class	HR-01	HR-2	HR-3	HR-4
Locobase ID	4430	5715	11061	3167
Railroad	Nacional de Mexico (NdeM)	Central Mexicano (NdeM)	Internacional Mexicano (NdeM)	Nacional de Mexico (NdeM)
Country	Mexico	Mexico	Mexico	Mexico
Whyte	2-6-6-2	2-6-6-2	2-6-6-2	2-6-6-2
Number in Class	10	1	20	8
Road Numbers	361-370	200 / 600 / 1100 / 2003	1101-1120/2004-2022	2030-2037
Gauge	3'	Std	Std	Std
Number Built	10	1	20	8
Builder	Alco-Schenectady	Burnham, Williams & Co	Baldwin	Alco-Schenectady
Year	1928	1908	1910	1937
Valve Gear	Baker	Walschaert	Walschaert	Walschaert
	Locomotive Length and Weight
Driver Wheelbase (ft / m)	16 / 4.88	18.67 / 5.69	21.34 / 6.50	21 / 6.40
Engine Wheelbase (ft / m)	37.50 / 11.43	44.17 / 13.46	46 / 14.02	49.58 / 15.11
Ratio of driving wheelbase to overall engine wheelbase	0.43	0.42	0.46	0.42
Overall Wheelbase (engine & tender) (ft / m)	64.50 / 19.66	70.92 / 21.62	79.21 / 24.14
Axle Loading (Maximum Weight per Axle) (lbs / kg)	28,672 / 13,005
Weight on Drivers (lbs / kg)	161,500 / 73,255	300,000 / 136,078	298,200 / 135,261	322,560 / 146,311
Engine Weight (lbs / kg)	204,000 / 92,533	338,000 / 153,314	338,500 / 153,541	400,960 / 181,873
Tender Loaded Weight (lbs / kg)	104,800 / 47,537	157,000 / 71,214	165,500 / 75,070	193,000 / 87,543
Total Engine and Tender Weight (lbs / kg)	308,800 / 140,070	495,000 / 224,528	504,000 / 228,611	593,960 / 269,416
Tender Water Capacity (gals / ML)	4500 / 17.05	9000 / 34.09	9000 / 34.09
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)	2500 / 9463	3500 / 13,248	4000 / 15,140
Minimum weight of rail (calculated) (lb/yd / kg/m)	45 / 22.50	83 / 41.50	83 / 41.50	90 / 45
	Geometry Relating to Tractive Effort
Driver Diameter (in / mm)	43 / 1092	55 / 1397	56 / 1422	57 / 1448
Boiler Pressure (psi / kPa)	210 / 14.50	200 / 13.80	220 / 15.20	250 / 17.20
High Pressure Cylinders (dia x stroke) (in / mm)	15" x 22" / 381x559 (4)	21.5" x 32" / 546x813	21.5" x 32" / 546x813	18" x 30" / 457x762 (4)
Low Pressure Cylinders (dia x stroke) (in / mm)		33" x 32" / 838x813	33" x 32" / 838x813
Tractive Effort (lbs / kg)	41,097 / 18641.31	64,193 / 29117.49	69,352 / 31457.58	72,474 / 32873.69
Factor of Adhesion (Weight on Drivers/Tractive Effort)	3.93	4.67	4.30	4.45
	Heating Ability
Tubes (number - dia) (in / mm)	123 - 2.25" / 57	350 - 2.25" / 57	365 - 2.25" / 57	164 - 2.25" / 57
Flues (number - dia) (in / mm)	28 - 5.5" / 140			40 - 5.5" / 140
Flue/Tube length (ft / m)	20 / 6.10	21 / 6.40	21 / 6.40	22 / 6.71
Firebox Area (sq ft / m2)	204 / 18.95	201 / 18.67	207 / 19.23	423 / 39.30
Grate Area (sq ft / m2)	52.50 / 4.88	61 / 5.67	67 / 6.23	70.30 / 6.53
Evaporative Heating Surface (sq ft / m2)	2449 / 227.60	4512 / 419.33	4701 / 436.90	3801 / 353.25
Superheating Surface (sq ft / m2)	680 / 63.20			1080 / 100.37
Combined Heating Surface (sq ft / m2)	3129 / 290.80	4512 / 419.33	4701 / 436.90	4881 / 453.62
Evaporative Heating Surface/Cylinder Volume	272.11	335.66	349.72	215.11

 

[mudchicken]

Sounds like a research request for the Colorado Railroad Museum Richardson Library. Robert W. Richardson Railroad Library and Collections - Colorado Railroad Museum

From all of Bob LaMassena's work and files, the DRGW archives and the tons of institutional knowledge of the DRGW retirees - I bet John Tudek and company would be able to find an answer to your question.

[pennytrains]

Have you tried the Denver and Rio Grande Western Historical Society?

 https://www.drgw.net/

 

[IA and eastern]

In WW1 Loree proposed seven 2-6-6-2s for the Marshall pass line and in 1920 the trustee proposed 2-6-6-2s with 44" drivers and 45,000 te but the board turned down both ideals. Are there any drawings or data on either of these proposals? Gary