Lionel’s new little K4 locomotive is a solid runner

Lionel’s new small K4 Pacific locomotive on track O. Model courtesy of Sommerfeld’s Trains & Hobbies, Butler, Wis. More information on

In the days of steam, many railroads had a particular locomotive that symbolized that railroad in the minds of the public. New York Central had 4-6-4 Hudson, Milwaukee Road had its streamlined Hiawata 4-4-2 Atlantics and the Pennsylvania – which called itself The Standard Railroad of the World – had the K4 class of 4-6-2 Pacifics.

Designed during World War I, development of the K4 was hampered by manufacturing restrictions. However, between 1914 and 1928, 425 examples were built.

In conventional and streamlined versions, they’ve handled some of the hottest passenger trains outside Pennsy’s electrified areas. They also pulled less exotic trains, but were still a reliable source of power!

In the O-gauge world, the K4 has long been a hot topic. Why, just in the last 30 years, Lionel, K-Line, MTH Electric Trains and Williams Trains have brought models of this classic into service in traditional and scale versions as well as sculpted brass models.

Opening the box

My first impression was that this appeared to be the older MTH RailKing K4 that I reviewed in 1997. After looking at the photos from this previous review, I could see similarities as well as notable differences.

Both models have the same basic outline and boiler grade metal casting. But the new version of Lionel has a lot more detail and looks more like a smaller scale model than a compromised design to fit tight radius curves.

Up front, the model has a solid “cow catcher” rather than a version with cast spokes. There are brakeman’s steps on both sides of the rider and in the center a dummy coupler.

The smoke box has many rivet and latch details. The smokebox mounted dead center is the famous Pennsylvania RR Keystone Herald in red with the engine number embossed in gold. Top and center is a large headlight with “1361” on both sides. Just behind you will find a turbine and the chimney.

The classification lights are positioned approximately midway between the turbine and the boiler handrails. Just behind the battery is an additional brass-colored bell with bell handle. You can move it back and forth with your finger.

Manufacturer’s plates are located on both sides of the smoke box. They read: “Juniata Shops K.4.s. & 1924 3910.”

Boiler has molded details for boiler bands, sand lines (two on each side) and steam dome drain pipes. The combustion chamber also has down-poured piping. Above the combustion chamber are two additional golden pop-off valves; a whistle comes from the side of the engineer.

Running boards aren’t just straight. Flat surfaces break and rise or fall above obstacles, such as air compressors. While the “rear” running boards serve a functional purpose, this is a nice variation that adds design depth to the overall look of the O gauge model.

Under the boards you will find the undercarriage. The rods are natural metal color. It looks sharp when running!

The locomotive cabin is beautiful. Like the rest of the locomotive, it is Brunswick green, but has a Tuscan red roof stripe. A hatch and cast rails are in the strip. The sides of the roof have cast rivets. The sides of the cabin arch downward and have two-pane window frames. The big visual is the combustion chamber. It has an eye-catching shimmering glow.

Two crew figures sit at their stations, and there’s overhead lighting so they can do their paperwork! It also shines the light of discovery on the rear head details. The crew arrives and departs using additional handrails on the cabin as well as on the front of the tender.

The tender has a five-step ladder for crew access. The body has a large bunker with a clearly defined “thick” coal charge. Behind the bunker is the water tank. The surface is painted red. There are cast rivets, a large cast water hatch and two overflow drains.

There are additional crew steps aft of the coal bunker. The stern of the dinghy has a cast ladder, platform, and supporting irons. There are ladders and handrails at both corners of the car; a plaque located at the rear reads, “No. 1361 Class K-4-1, engine number 1361.”

The remote coupler is rear mounted. Finally, the painting and decoration of the model are simple but excellent, just like on the prototype.

On the test track

We ran this Lionel model using an MTH Z-4000 transformer and the LionChief app. The operation was flawless. Orders are received and launched immediately. When you change direction while driving, the motor gently slows to a stop, then gently slows in the other direction.

The glow from the combustion chamber is fantastic! The flickering light on the crew members adds to the scene, especially in the dim light.

The smoke unit emits a nice stream of visible smoke, but not enough to cause an operator to choke. The undercarriage is as quiet as I’ve heard in a while.

Our low-speed average in conventional mode was 4.5 scale miles per hour, while slow speed in command mode was 3.2. smph. Our high speed was 86.1 smph.

The drawbar pull was 2 pounds and 2 ounces. The motor and speed control really increased when it met resistance from the dyno. The momentum slowed when the resistance was removed.

The Lionel Baby K4 Pacific may only be 19 years old12” long, but the 4-6-2 delivers excellent performance and a high level of detail to a fleet of traditional sized locomotives. If you’re a Pennsylvania RR fan or someone who collects classic steam-era engines, check out this model at your local Lionel retailer. –Bob Keller

More product reviews here.

Facts and Features of Lionel’s LionChief 2.0 Plus Baby K4 O Gauge

  • Price: $549.99 (#2312090)
  • Features: O-31 Operation, Die Cast Metal, Lionel RailSounds, Fan Driven Smoke Unit, Remote Coupler on Dinghy. Equipped LionChief 2.0 Plus Command; can be controlled via Bluetooth using the Universal Remote or the LionChief app. Can also be used with Lionel Train-Master or Legacy control systems or a conventional transformer.
  • Cmd. low: 3.2 miles per hour
  • Cnv. low: 4.5 miles per hour
  • High speed: 86.1 miles per hour
  • Current road names: Brunswick Green and Tuscan Red Pennsylvania RR nos. 1361, 3750, 5400 and in Tuscan red no. 5409
Black Lionel's new small K4 locomotive.
This traditionally sized Pacific captures the Pennsy spirit. Model courtesy of Sommerfeld’s Trains & Hobbies, Butler, Wis. More information on

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