Review by Tony Cook/model photos by the author
PIKO America’s excellent reproduction of German locomotive builder Krauss-Maffei’s ML4000 returns with new versions decorated for Denver & Rio Grande Western (D&RGW) and Southern Pacific (SP).
This fully assembled HO scale model is one of those efforts that makes you wish a manufacturer would offer more releases. PIKO America’s North American prototype offerings in 1:87 are limited, compared to the vast collection of European subjects the company catalogs. For this reason, some hobbyists pursuing North American prototypes likely do not have PIKO America on their radar. This six-axle diesel-hydraulic locomotive replica is a standout and I am certain I am not the only collector that remains impressed with this ML4000 and looks to the future for more from this hobby company.
When this HO model project was announced, the company stated later looks for these 1960s era locomotives would be future releases following the debut run’s as-delivered examples. What is on display in this review is a later look for the ML4000, and based on Rio Grande’s group of three units. Troubled by exhaust overtaking the necessary quality air for good operation (not unlike the pursuit of Tunnel Motors to come from Electro-Motive), two openings were added to the lower sides of D&RGW’s ML4000s. This feature and the rooftop tanks are additions to the tooling for this production run. Check your February and September 2025 editions of Model Railroad News to see previous Rio Grande and Southern Pacific models from PIKO America and you’ll quickly spot many differences between as-delivered ML4000s from those runs and this modified edition release.
ABOVE: SP 9022 shows the patched Rio Grande livery look PIKO presents in this new locomotive release. You’ll notice the air intake panels on the lower body side near the center unit and addition of rooftop tanks. When Rio Grande management decided they had experimented enough with the diesel-hydraulic concept, Southern Pacific picked up the trio of Rio Grande units. —Kevin EuDaly collection
In addition to the tooling revisions, PIKO America presents its Southern Pacific 9022 with a faded appearance to the single-stripe Aspen Gold and silver Rio Grande livery. When SP acquired D&RGW’s trio of ML4000s, which differed from the look of the units Southern Pacific took delivery of in 1961 (same time the Rio Grande units arrived from Germany), the new owner initially removed flying Rio Grande lettering and 4000-series numbering and applied black Southern Pacific lettering on the sides, an “SP” on the nose, and 9000-series numbering.
PIKO’s fading is subtle, but well executed. My photos illustrate the lighter/faded hues, but in person they are even more obvious and quite authentic looking. Check out the photo on the facing page of SP 9022 in patched Rio Grande paint, and you will see, with some weathering applied, this new PIKO America modified ML4000 model dressed for SP could be an eye-catching addition to your roster.
ABOVE: The ML4000 tooling includes modifications and additions to the detailed plastic body shells. You’ll spot two added grilles along the lower body sides. These served to improve the quality of air brought into the unit. Tanks on the roof are additions for this modified appearance. PIKO America presents Rio Grande livery on these two releases, but note the faded quality of the Aspen Gold hue on Southern Pacific 9022 (right).
Like the previous ML4000 releases, buyers will find this finely rendered miniature offered with a standard DC setup or with PIKO’s TrainSounds electronics providing audio features, and digital operation and control of lighting and sound functions.
The model is an Expert series release in PIKO America’s line and comes secured on two posts on a plastic base. The model is not secured by screws, but simply lifts up and off its base. A guide is included for DCC operations and should be examined before you fire up your ML4000 and attempt to head out on your main line, as the usual European mapping of functions is present. These features can be revised to follow the North American locations you may be more familiar with when going to select a throttle function. I’m eager to see PIKO America return with more, and hope to see the company add other exotic prototypes to its line like this wonderful ML4000.
