The much-anticipated Krauss-Maffei ML-4000 diesel-hydraulic locomotive is now available from PIKO America. The newly tooled model, based on the 1961 prototype, has an injection-molded plastic body, die-cast metal chassis, and can motor with dual flywheels.
Prototype history
The PIKO America models are decorated as Southern Pacific 9000, 9001, and 9002 in their as-delivered appearance. The full-size units, originally part of the railroad’s DF-800 class, were built in Munich, Germany, in June 1961 and delivered to the Port of Houston in October. The units, based out of the railroad’s Roseville, Calif., shops, entered service in early November.
What is a diesel-hydraulic locomotive? The ML-4000 had two Maybach diesel engines that powered a pair of Voith hydraulic transmissions instead of generators and traction motors. Driveshafts connected the transmissions to the geared axles.
In October 1965, the engines were renumbered 9100 through 9102 and reassigned to the KF636A-1 class. The three units were retired between Sep-tember 1967 and June 1968.
Model features
The plastic body, which has a separate nose, features a mix of molded and freestanding parts. Factory-applied parts include the wire grab irons, handrails, and lift rings; plastic air compressor intercooler pipes; and etched-metal fan and intake screens. The truck sideframes are based on the all-welded style used on the 1961 prototypes.
Our review sample is decorated as Southern Pacific 9000. The gray and scarlet paint is smooth and evenly applied, and the separation lines between colors are crisp. The decoration and lettering placement matches a photo in Southern Pacific Motive Power Annual 1968-1969 (Chatham Publishing Co.)
The model’s dimensions closely follow prototype drawings published in the October 1984 Mainline Modeler. The distance over the coupler pulling faces is a couple of scale inches long, but this is typical, as model couplers are oversized.
On the test track
The sample we received is equipped with a SmartDecoder XP 5.1 sound decoder. Models sold through PIKO America and its dealers have 27-function decoders designed for use with NCE and other North American Digital Command Control (DCC) systems. Versions sold outside the United States have decoders that follow European DCC protocol.
Of note, F8 (motor sounds), F9 (number boxes and class lights), and F15 (lighting double traction) are multi-step functions. For example, if you press F8 once, a single engine starts. Press it twice and the second engine start-up sequence begins. A third press mutes the engine sounds; four turns all sounds off.
I tested the locomotive in DCC with an NCE Power Cab in our workshop. At step 2 the model moved at less than 3 scale mph. The engine achieved a top speed of 71 scale mph at step 28. The maximum speed on the prototypes was 70 mph.
I then took the model over to our Milwaukee, Racine & Troy layout for further testing. The locomotive led a train over the main line without incident. It was able to pull 14 50-foot boxcars up the 3 percent grade between Williams Bay and Skyridge.
For many years, brass imports or the Rivarossi/AHM plastic model were the only options if you wanted an ML-4000 in HO scale. Thanks to PIKO America, you can have a model with modern features. If you model the SP in the 1960s, this engine deserves a spot in your diesel fleet.
Watch a video of the PIKO America HO scale diesel-hydraulic locomotive in operation on Trains.com.
Facts & features
Price: Two-rail model with SmartDecoder XP 5.1 and sound, $399.99. Direct-current model with PluX22 decoder interface, $279.99. Three-rail model with decoder and sound, $409.99.
Manufacturer
PIKO America LLC
4610 Alvarado Canyon Rd., Ste. 5
San Diego, CA 92120
Era: November 1961 to October 1965
Road names: Southern Pacific (scarlet-and-gray scheme, as-delivered details). Road numbers 9001, 9002, and 9003.
Features
- PIKO knuckle couplers, at correct height (trip pins slightly low)
- RP-25 contour wheels, in gauge
- Weight: 1 pound, 6 ounces
I wish Piko would do this in N!