Mountain Models (division of PSC) K-27 in On30

Reviewed by Chris Lane/Model photos by the author; prototype photos as indicated

The K-27 class, outside-frame Mikado of the Rio Grande and Rio Grande Southern railroads have long been a favorite of modelers and railfans. This brass and die-cast metal rendition of the K-27 is the first effort from Mountain Models, a new division of long-time brass importer and detail part supplier Precision Scale Company. The model comes factory painted and lettered, DCC ready with a DC sound system installed and is studded with detail. In a word, it is awesome.

The Prototype

The K-27s enjoyed a long and varied career on Colorado narrow gauge railroads. Originally designated Class 125 (weight of 125,500 lbs.) 15 locomotives numbered 450-464 started arriving from Bald-win in March 1903. The as-delivered locomotive bore little resemblance to the model photos shown. They came equipped with slope-backed tenders, huge box headlights, spoked lead-truck wheels and the Vauclain Compound cylinder arrangement. Named for Samuel Vauclain, a Baldwin employee from 1881 until his death in 1940, compounding was touted for two reasons. One, it makes the locomotive a four-cycle machine instead of the normal two-cycle, resulting in a smoother running locomotive that is better able to avoid stalling at slow speed. Second, Baldwin emphasized the obvious economy of using steam twice. Once in a high pressure set of cylinders, then again in larger, low-pressure cylinders. They also claimed that the smoother, better draft resulting from the eight impulses of power per driver rotation was thriftier on fuel and water.

The reality of their early service didn’t make any Baldwin promotional catalogs, as the series was plagued with problems from the moment they were set up for service in the Salida shops. The locomotives were so much larger than the other D&RG motive power that they required the rail to be upgraded and bridges to be strengthened from Salida over Marshall Pass to Gunnison. Local newspapers reported that the new engines broke rail and spread the gauge for quite sometime after their arrival. The Salida Record newspaper dubbed them “little monsters,” but the locomotive’s waddling gait at any speed soon had the enginemen referring to them as “Mudhens,” and the nickname stuck throughout their service life on the Grande. The enginemen found them to be slippery and not nearly as powerful as advertised. Newspaper reports from the period indicate the railroad was generally disappointed with their service, and they were spending a fair bit of time in the shop. The locomotives proved to be no favorites of the shop crews either.

No. 464 as originally delivered from Baldwin. Note the compound cylinders, slopeback tender, original stack and headlight. Colorado Railroad Museum collection

Salida had extensive dual-gauge trackage, and the narrow gauge rail was smaller than the standard gauge rail when the Mudhens arrived. This resulted in the narrow gauge locomotives “listing” as they moved around the yard. For the smaller inside-frame locomotives, that presented no problem, but the Mudhens had less than an inch of clearance between the main rod and the top of the standard gauge rail. Any miss-calculation in turning the driver diameter or the wedges on the driver boxes would result in a bone-rattling crunch for engine and enginemen.

The intricate machinery of the compound arrangement also proved troublesome. A compound engine can’t admit steam into the low-pressure cylinders until the high-pressure set has completed a full cycle. Baldwin configured the design with a bypass valve to admit high-pressure steam to both sets of cylinders to start the train. The engineer was supposed to close the bypass valve after the first driver rotation, but the tough operating conditions over Marshall Pass tempted the enginemen to use the bypass valve for extended periods. Because the low-pressure cylinders had three times the volume of the high-pressure set, running both at the same pressure caused differential stress to the running gear and extensive maintenance to the compound mechanism.

By late 1905, the D&RG realized that the maintenance expense and sub-par performance of the compounds far exceeded the fuel savings so the decision was made to equip a single Mudhen with standard slide valves as an experiment. No. 458 was the first to need heavy repairs and was sent to the Burnham shops in Denver for conversion in June 1906. Returned to service in February 1907, the locomotive’s performance was much improved, and it was capable of greater tonnage than before. In fairness, part of the performance has to be attributed to the enginemen’s experience operating “simple” slide valve locomotives, but the D&RG was convinced this was a worthwhile measure and authorized the conversion to slide valves of the entire class. Engines 450, 452, 455, 461 and 463 were converted between December 1908 and September 1909. The rest were converted by January 1912 with the exception of 456, which the railroad didn’t get around to until April 1916. The railroad added a second 91/2" air pump in 1912 and generators, electric headlights and new stacks in 1915. The slope-back tenders were replaced in 1918 with larger, square tanks. The shop specs called for a 9" radius on the rear corners, but the first two tanks built for 453 and 464 were virtually square.

No. 460 in Sadila in slide-valve configuration. This was the last slide-valve K-27 in service, lasting until 1939. Colorado Railroad Museum collection

In 1921, the Denver and Rio Grande reorganized as the Denver & Rio Grande Western, and in 1924 the Class 125 locomotives became K-27s. They also would undergo their final conversion. Back in 1917 an industrial consultant, who was also president of the Delaware & Hudson Railroad, was hired to examine the entire system. His recommendations for upgrading the rail and bridges on the narrow gauge were largely accomplished by the early 1920s, and the Mudhens, once restricted to the Marshall Pass and Cerro Summit lines, were being used system-wide. The one motive power recommendation was that the K-27s would benefit from conversion to piston valves and Walshaerts valve gear and from superheating. No. 454 was the first to be converted in 1924, followed by 461, 458 and finally 456. All of these were inside-admission piston valves, which gave the appearance of the cylinder set leaning in toward the boiler.

After evaluation, the D&RGW decided to equip the remainder of the conversions with a different linkage on the inside-admission piston valves, which gave the appearance of the cylinder set leaning away from the boiler. No. 464 was converted in 1925, followed closely by 452 and 455; 455 also received superheating at the time of conversion. The other K-27s didn’t get superheating until 1927 and 1928. Like the previous conversion to slide valve, once the initial group of locos was converted, the pace slackened considerably. The last K-27 to be converted was 462, and it didn’t leave the shop until 1929. It also never received superheaters and its “second-class” status relegated its service to the Silverton branch and the Rio Grande Southern. Due to the business downturn of the Depression, and the addition of the K-36 class in 1925 and the K-37 class in 1928 and 1930, the remaining K-27s (450, 451, 457 and 460) were never converted and finished their service as slide valve, saturated steam locomotives.

In their final configuration, the Mudhens were considered the best riding and running locomotives on the entire system by a number of veteran enginemen, even preferred over the standard gauge engines.

Final configuration showing the piston valves located outside the cylinder centerline and Walschaerts valve gear. When captured on film by Richard Kindig in Montrose, 452 had been in service for more than 40 years but still had more miles left before its 1954 scrapping. Richard Kindig photo, Colorado Railroad Museum collection

The K-27s continued to run up the miles working out of Salida, Gunnison and Durango on the Silverton branch and also the RGS. The first K-27s to leave the roster were the unconverted slide-valve engines in the early 1930s. No. 460 worked out of Gunnison in snowplow duty and as a back-up locomotive until 1938. No. 455 was traded to the RGS for ditcher 030 in 1939. In 1941, 458 and 459 were sold the Nacionales de Mexico and lasted until the late 1950s or early 1960s. No. 462 was next to go in 1950 along with 456. No. 461 was on the way to the scrapyard when the RGS inexplicably bought her to use for their last season in 1951. Both the 461 and 455 were cut up in the Ridgway shops in 1953. No. 454 turned her last wheel in 1953, as did 453. Long the Silverton mixed power and Durango switcher, 453’s boiler was sold to a lumber company, and the remains joined 452 for scrapping in 1954.

Nos. 463 and 464 were the last K-27s on the roster and worked out of Durango. No. 463 was sold to cowboy film star Gene Autry in 1955. Never used, it was donated by Autry to the city of Antonito in 1970 for use on the newly formed Cumbres & Toltec Scenic Railway. A restoration effort was started in the early 1970s but never progressed very far. The locomotive languished in the Antonito engine house for many years. The city donated the locomotive to the Cumbres & Toltec in 1989, and in 1992 a full-scale restoration effort was begun under the direction of John Bush and the Chama engine house staff. They built a new tender tank and cab, turned all the drivers, rebuilt the lead and trailing trucks and did extensive boiler and running gear work. In 1994, the 463 steamed out of the Chama engine house and faithfully served the CATS until a side rod breakage in 2002 sidelined her. A change in railroad management and work on other locomotives has kept her inactive, but the locomotive is basically sound and is the odds-on favorite to be the next to be returned to service.

No. 463 is seen in almost the same spot as 453. Note the subtle differences in piping, but it’s really remarkable how similar the locomotives look after three major rebuildings and 50 years of service. Colorado Railroad Museum collection

The 464 was the last active K-27 and used off and on until 1957. In retirement, it was used for spare parts on the Silverton K-28s and sat derelict in the Durango yards until 1973. I climbed on the engine in 1973 and can attest that all the fittings in the cab were gone, and the loco was in rough shape. Sold to Knott’s Berry Farm, the K-27 joined 2-8-0s D&RGW 340 and RGS 41 along with some ex-San Juan passenger cars. Restored and converted to burning oil, the 464 was used for no more than two seasons before management decided it was too big for the tight radius track in the park and sold it to the Huckleberry Railroad in Michigan in 1981. Restored to operation in 1989, it operated with a former White Pass & Yukon 4-6-0. When the ten-wheeler needed heavy repairs in 1990, 464 was the Huckleberry’s only motive power and used for several years. When the ten-wheeler returned to service, the Mudhen was again withdrawn, and the Huckleberry crew embarked on an extensive, multi-year rebuild culminating with the K-27’s boiler being steamed in May of 2005. The shop plans to finish the remainder of the work in time for the National Narrow Gauge Convention in August. It looks like 2006 will be a year that sees both surviving K-27s in prime operating condition. For additional information, find a copy of Dennis Berry’s excellent reference, The Mudhens (R/Rob). Much of the information in this article came from that book and Allen Brewster’s two-part article in the May and June 1973 Model Railroader.

The Model

My sample arrived in a heavy, brass-locomotive-type box. After removing the top foam I found two cardboard boxes nestled in the foam. These contain the tender and locomotive sitting on their wheels. You start to understand the packing as you remove the locomotive and tender from their boxes — they are very heavy! The die-cast and brass construction makes the tender 1 lb, 6 oz and the locomotive 3 lbs, 2 oz for a bridge-busting total of 41/2 lbs.! The weight, combined with the hefty can motor easily pinned our 9-oz test fixture, making it the best pulling locomotive we’ve ever tested. The K-27 I received for review did not yet have the sound system installed, so I was able to test the performance without any electronics. The locomotive ran smoothly, slowly and silently. I was very impressed with the out-of-the-box running characteristics, and it’s flat fun to watch those big outside counterweights lazily rotate. Mountain Models says the minimum radius for 0n30 is 26" and 0n3 34". The 26" minimum radius seems to be about right. Mountain Model did some clever things to get as much swing out of the lead and trailing trucks as possible, but this is the biggest On30 locomotive produced so far, and it needs wider curves.

The appearance of the model is nothing short of stunning. PSC has long supplied brass detail castings to the hobby, and this locomotive is dripping with them. It is basically a brass engine with a die-cast body. The model sports all the piping of the prototype save some minor lubricator lines and has a full cab interior complete with painted gauges and valve handles. As you can imagine with all the rebuilding, the prototypes had minor variations in piping; this model’s piping most closely resembles 453’s. While the model can’t match all the little detail variations of every outboard-cylinder-type K-27, Mountain Models went to the extra trouble of adding a few prototype specific details. For instance, many, but not all K27s had conduit on the roof for cab wiring. The 452 has it, but 453 didn’t and neither does my personal On3 model of 453. Also, 453 was the only K-27 to ever have a doghouse, which it featured in its last years working out of Durango. My 453 has the earlier green boiler paint scheme and comes sans doghouse, but all the models of 453 in the later “Flying Rio Grande” scheme have the doghouse included. A very nice touch on Mountain Models’ part. Conduit to the marker lamps, full engine brake rigging, cylinder cock piping... This model is loaded with detail.

I checked the model dimensions against Allan Brewster’s June 1973 plans in MR and the D&RGW locomotive folios and found the locomotive to be very accurate except for the frame and the cylinders which are a few inches wider than scale. I’m sure this was done to give the drivers a bit more lateral movement. The discrepancy is visually undetectable, and every other dimension checked was dead on the money, including the driver diameter. This is where the HO folks have to compromise, but that is not needed in On3/On30. The ultra nitpicker would point out that the flange on the tender tank and the boiler jacket clamps are both thicker than scale, but neither detracts from the overall excellent appearance of the locomotive.

The model comes in three schemes, with Rio Grande Southern’s “sunset” herald, the D&RGW’s post-1940 “Flying Rio Grande,” and the “Scenic Line” herald and green boiler jacket. The Durango and Salida shops applied the green boiler jacketing to select locomotives in the 1920s and ’40s. Having examined locomotives in both schemes, I give Mountain Models very high marks on each. Color separation on the green boiler scheme is excellent, and all dimensional data is correct and properly located.

The model comes from the factory DCC ready and equipped with a DC sound system and speaker installed in the tender. (The sound board came separate on my review sample because it was built before the boards were ready, so I had to install it.) Also installed is an octagonal sound cam on the first axle to activate the exhaust chuff. The sound system can also be used with DCC with the addition of the NCE D18SRPSC decoder. As has happened with a number of manufacturers when they first added DCC plugs and sound, a few issues with the electronics/sound system in the K-27 have cropped up after release. It was found that the sound system does not respond well to some DC power packs. To PSC’s credit, they immediately acknowledged the problem and are offering a $25 control box free of charge to locomotive owners. Similar to the BLI Sidekick whistle/bell controller, the box contains filters that reportedly solve the problem. Details are on their website at www.precisionscaleco.com, and there are also instructions for disconnecting the speaker for silent operation, DCC installation and complete removal of the sound system for DC operation.

At press time, the control box was not yet available so I requested and received the D18SR-PSC decoder from NCE. Installation was quickly and easily done following NCE’s instructions. I did have to turn the DCC plug 90° due to the tight fit of the tender, but the plug is mounted using double-sided foam tape, and this is easily accomplished. Don’t forget to add the provided resistor or you’ll fry the 1.5V bulbs in the headlight and cab (guess how I know that)! Throttle response was very good.

Mountain Models Division of Precision Scale Models PO Box 278 Stevensville, MT 59870 D&RGW K-27, black and graphite w/flying Rio Grande — 452, 453, 459, 462, 463, 464, unlettered (On30, DC1001-1 to -7; On3, DC1007-1 to -6) D&RGW K-27, w/green boiler, D&RGW herald — 452, 453, 459, 462, 463, 464 (On30, DC1003-1 to -6; On3 DC1009-1 to -6) D&RGW K-27, black and graphite, Rio Grande Southern 455 (On30, DC1005-1; On3, DC1011-1) MSRP $489.00

NCE has provided a nice drop-in solution for those who want to use the stock sound system with DCC (The D18SR-PSC decoder, which is rated at 1.3 amp with a 2 amp peak, retails for $34.95 and is offered by NCE Corp., 899 Ridge Road, Webster, NY 14580). Once I verified that the decoder was working properly, I tested the sound system. As with most sound systems, the factory setting is far too loud. There is a square pot attached to wires coming off the soundboard; you’ll want to turn it down about half way. Sound is a highly subjective area, but the sound generated by this unit is a bit disappointing. The whistle is a good sample of 463’s distinctive single chime, and the bell is good, but the chuff sounds have more of a static quality than steam exhaust, and the background clanking, which I assume is the air compressor, misses the mark. In spite of the unit’s sonic shortcomings, it functions as it is supposed to and adds some additional locomotive sounds. I’d rate it on par with QSI’s and MRC’s early efforts. It’s really not a case of the sound system being bad, as much as the rest of the locomotive is so darn good, it suffers in comparison.

Mountain Models has hit its first effort out of the park. This K-27 stands alone at the summit of On30 locomotives and makes no apologies to any brass On3 locomotives costing three and four times as much. By cleverly building the locomotive in both On3 and On30, PSC’s new company has maximized their market and given both gauges an almost flawless model. They’ve also announced a K-28 for later this year, the inboard cylinder K-27, a K-36 and K-37.

This review originally appeared in the July 2005 Model Railroading.