Railroad Model Craftsman

Subscribe Today!

Meet the Staff

Craftsman Timetable

Craftsman Product Reviews

Craftsman Extra Board

Craftsman Boomer Trail

Craftsman Tool Chest

Find us on Facebook

Support our Sponsors

Bachmann Spectrum 70 Ton 3-Truck Climax Locomotive in HO Scale
Bachmann has introduced a new Class C (three-truck) version of their HO Climax locomotive that comes factory equipped with DCC and Soundtraxx Tsunami sound. This is a nicely proportioned, well-detailed, prototypically accurate, smooth running model with great sound features, especially when operated in the DCC mode.

Review: Bachmann Spectrum 70 Ton 3-Truck Climax Locomotive in HO Scale

by Gary Quale /photos by the author

Bachmann has introduced a new Class C (three-truck) version of their HO Climax locomotive that comes factory equipped with DCC and Soundtraxx Tsunami sound. Only a few scale plans and only three Class C Climax locomotives survive today: the 1909 75 ton #3 of the Northern California Lumber Co. and later of the Fruit Growers Express Co. now on display in Los Angeles, the 1919 70 ton Moore-Keppel & Co. #6 now being restored at Cass WV as their #9, and the 1928 70 ton Hillcrest Lumber Co. #3 (later renumbered 10) now operating at the Mt. Rainier Scenic RR. Bachmann has made a good choice of the very typical locomotive at Cass as their prototype.

The Climax locomotive, like Ephraim Shay's invention of 1877, was the creation of a lumberman seeking a better way to haul logs out of the woods. Charles Darwin Scott built a tram road circa 1875 for his logging business near Spartansburg, Pennsylvania, and by 1878 had created a locomotive to improve operations. Believing he had a marketable design, Scott took his plans to the Climax Manufacturing Co. in Corry, Pennsylvania, which was already producing stationary engines. Early records are sketchy but indicate commercial production began by early 1888. Scott's in-law George Gilbert was an engineer and draftsman with the Climax firm, and offered to assist in preparing a patent application. The patent granted in December 1888 is interesting in that Gilbert did not include Scott's name on the document.

The original Climax locomotives, which came to be identified as the Class A design, were typically a wooden platform with a vertical boiler and two-cylinder vertical engine mounted in the center with a rectangular fuel bunker at the boiler end of the platform and a circular water tank at the other end. Unique features included a gearshift arrangement that offered overall drive ratios of either 4½:1 or 9:1, a centered longitudinal countershaft driving all four axles via skew gears, and differentials on each axle allowing the wheels on each side to operate at different speeds on sharp curves. They were offered in sizes from 12 to 22 tons in gauges from 24" to 8' and with wheels for steel or wooden rails or for pole roads. A class A Climax was under construction when the factory closed in 1928.

Bachmann Spectrum 70 Ton 3-Truck Climax Locomotive in HO Scale

The two-truck Class B Climax was introduced in 1890 to meet the demand for a larger locomotive. The original Class B design included the gearshift and trucks with differentials as on the Class A. The engine was changed to two horizontal cylinders mounted in about the same position as on a conventional rod locomotive. These operated a transverse crankshaft that was connected to the longitudinal countershaft through 90o skew gears. In 1893, the Class B was redesigned to eliminate the gearshift and differentials, and to incline the cylinders at about 22½o. Class B's were offered in sizes from 17 to 62 tons and accounted for about 65% of all Climax production.

Several improvements were made over the years. Wagon-top boilers were substituted for the original straight boilers on larger locomotives. Steel cabs were offered beginning in 1910 when the flared-flange at the top edge of the tank was replaced by a squared-off top with simple edge bead. Paired cab side windows were replaced with a single side window after 1913. Walschaerts valve gear was used instead of Stephenson on 45 ton and larger locos beginning in 1915.

The three-truck Class C was first offered in 1897. The first was only 50 tons and the only narrow gauge Class C (and it was eventually converted to standard gauge). It was found that the Class C tracked better than the larger Class B's with their longer wheelbase between trucks. Class C's were standardized in 70, 80 and 90 ton sizes. Evolutionary changes on the Class C's paralleled those on the Class B. In addition, the Class C began using piston valves with optional superheat in 1923, received girder frames without truss rods and vestibule rather than open cabs in 1925, and had archbar trucks replaced with a cast steel sideframe. Climax built their first 100-ton Class C in 1923 with many of these improvements. The locomotive was displayed at the Pacific Logging Congress and promptly sold to a Washington State logger. These improved Climax Class C locomotives were ideal for the Northwest woods, and were not matched until the introduction of the West Coast Special Heisler and the Pacific Coast Shay a few years later.

The Bachmann Class C model features a wagon top boiler, single window open steel cab, truss rod frame, archbar trucks, and slide valves with Walschaerts gear. These details are appropriate to a locomotive produced in the 1915 to 1923 time frame, including Moore-Keppel & Co. number 6 built right in the middle of this time period. There is one photograph of M-K #6 in Thompson, Dunn & Hauff's book The Climax Locomotive, and another almost identical photo but with the name painted out and renumbered as #9 at the excellent Climax Locomotive web site. These three quarter views of the fireman's side show details that closely match the Bachmann model. One exception is that these photos show a single-phase air pump, while our unlettered sample has a cross compound unit. Bachmann states that other lettered versions do come with the appropriate type of air pump. These photos also show a long suction hose coming out from between the fuel bunker and water tank, drooping behind the cab steps, and ending just under the running board above the Walschaerts link. This would have been used with a steam eductor to draw water out of a convenient creek for refilling the tank, and would be an easy detail addition to the model. The model comes equipped with a straight stack as on M-K #6 installed and an optional Cass-style balloon stack. Similarly the model comes with a coal pile in the fuel bunker and an optional oil fuel bunker top. The model also has a detailed cab interior.

Bachmann Spectrum 70 Ton 3-Truck Climax Locomotive in HO Scale

Bachmann has made one interesting change from the Climax design for the countershaft dive train. On the prototype, the gears connecting the crankshaft to the longitudinal counter shaft, and the gears connecting the countershaft to the axles, are all skew gears as their shafts do not intersect, but rather pass above and below each other. Bachmann simulates this arrangement on the model for the crankshaft to countershaft shafts. But apparently to reduce the height of the drive train, Bachmann uses miter gears between the countershaft and the axles. Because the shafts of miter gears are in the same plane and intersect, the model has to break the longitudinal counter shaft at every axle. The driving miter gear on the counter shaft drive drives a mating miter gear on the axle, which in turn drives another miter gear on the continuation of the counter shaft to transmit power to the next axle, etc., etc. Thus while a prototype Climax transmits power from the crankshaft through only two pairs of gears to drive the any axle, the model transmits power through eight pairs of gears to drive the last rear axle. This could potentially add mechanical inefficiency and backlash to the drive train, but does not seem to be a problem in our DCC tests. This arrangement has the interesting side effect that each portion of the counter shaft rotates in the opposite direction of its neighbors. The model picks up power through all six wheelsets and comes with factory installed E-Z Mate Mark II couplers.

The use of miter gears with their 1:1 ratio results in the axles and counter shaft rotating at the same speed. This differs from the prototype, where most of the gear reduction was in the countershaft to axle gears, but is not noticeable. Counting teeth in photos of the restoration progress at the Mountain State Railroad & Logging Historical Association web site, it looks like the countershaft gear has 16 teeth and the axle ring gear has 41 for a reduction ratio of 2.56:1. We did not locate photos of the crankshaft to countershaft gears that were as clear, but these appear to be about the same size so they add little or no additional gear reduction added to the Climax drive train. The model appears to have similar reduction ratio in that the crankshaft turns between 2 ½ to 3 times for one revolution of the drive wheels. The model operated on 15-inch radius curves on our test track. The countershaft drive rods to the front truck and between the second and third trucks are quite short, and can become disconnected in handling the loco if the trucks are allowed to swivel to their limits. It was not difficult to reconnect these shaft connections without having to remove the trucks.

Bachmann Spectrum 70 Ton 3-Truck Climax Locomotive in HO Scale

The Bachmann Class C Climax reviewed came equipped with a dual-mode NMRA-compliant sound decoder with 8-pin plug. In the analog DC mode the locomotive woke up at about 5 VDC with the yellowish directional headlight on and air compressor sounds. Increasing the voltage to about 7.5 vDC initiated chuffing sound effects, but the voltage had to be increased to about 8.5 vDC before the motor would move the locomotive at a steady 4 ¾ scale mph. This should improve with additional break-in of the drive train. At 12 vDC current draw was 0.1 A and the speed 10.7 SMPH. Holding the coupler to cause wheel slip increased the current to just under 0.2 A. At 16 vDC the speed was 20 scale mph, a little above the typical maximum for a Climax. In the DCC mode and using a Digitrax DCC system speed step 1 resulted in a smooth speed of under 0.9 SMPH (that's 3 ¼ minutes to travel 12 actual inches)! Speed step 99 had a speed of 19.5 SMPH. The model weighs 10.4 oz. and we measured a drawbar pull of 1.3 oz.


Bachmann Trains
1400 East Erie Avenue
Philadelphia, Pennsylvania 19124

Class C Climax, 70-ton, 3-truck
HO Scale

MSRP: $535.00 (sound-equipped)

82926 - Painted, Unlettered - Black
82927 - Painted, Unlettered - Black with Red Windows and White Stripes
82928 - Moore-Keppel & Co. #6
82929 - Cass Scenic RR #9
82930 - Clear Lake Lumber Co. #12
82931 - Climax #3 (Demonstrator)

MSRP: $385.00 (dual-mode decoder):

82901 – Painted, Unlettered – Black
82903 - Moore-Keppel & Co. #6
82904 – Cass Scenic RR #9
82905 – Clear Lake Lumber Co. #12
82906 – Climax #3 (Demonstrator)

The sample Climax came with a Soundtraxx Tsunami 16-bit sound decoder. In the DC analog mode, the decoder provides chuff sounds when moving, air compressor sounds when stationary, and one, two or three short whistle blasts when stopping, starting or backing. In addition, the decoder can be programmed to provide automatic grade crossing whistle signals, bell signals, steam release on stopping, and brake squeal when slowing. In the DCC mode, the sound decoder provides a full range of operator controlled and automatically programmed sound effects, and CV-controlled adjustments. The decoder includes a 1-Watt audio amplifier, which at factory volume setting is good for hobby shop demonstrations but is a little loud for use on a layout with other sound equipped locomotives. Sound quality is very good. The chuff rate is programmed using the Soundtraxx Auto-Exhaust feature rather than a physical cam. At low speeds, the factory setting resulted in about 3 ½ chuffs per revolution of the crankshaft that seems close enough for realistic chuff sounds. At about speed step 40 and a track speed of about 10 ½ scale mph the individual chuff sound transitioned into a continuous "whoosh."

This is a nicely proportioned, well-detailed, prototypically accurate, smooth running model with great sound features, especially when operated in the DCC mode.


About Our Company

White River Productions


Our Publications

Railroad Model Craftsman

Model Railroad News

Railfan & Railroad

Passenger Train Journal

TRP Magazine

Railroads Illustrated

On30 Annual

HOn3 Annual

Shop Our Products

Subscribe Today



White River Productions

©2009-2015 All Rights Reserved :: White River Productions :: P.O. Box 48 :: Bucklin, MO 64631 :: (816) 285-6560