The Big Boy - Faithfully realized by Märklin and TRIX

The refurbishment and commissioning of the world's largest steam locomotive - the Big Boy 4014 - on the occasion of the Golden Spike anniversary in 2019 caused a sensation.

This powerful locomotive, which we already had in our program, has now been reissued for the year 2020 to bring the remanufactured original as perfectly as possible onto the model railroad tracks.

The many design changes to the prototype were also implemented on the new machine from Märklin and Trix. The differences to previous models are summarized on this page.

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In 14 steps to the masterpiece


#1 Oil Tender

The prototype was converted to oil firing. For this purpose a tender of a Challenger was coupled to the prototype. On the Märklin model, the previous coal tender was converted to an oil tender and the tool box and the surrounding railing were added.


#2 Small changes

Tender front wall modified according to the prototype.

#3 Additional steps

At the rear of the tender, the water filling nozzles and the additional steps were installed.

#4 Train control

The box for train control at the oil tender was added on the right in the direction of travel.

#5 Oil firing

By converting the locomotive to oil firing, the ash pan was removed.

#6 Removing the handwheels

The handwheels have been removed from the prototype as well as from the model.

#7 Changes to the back wall of the upright boiler

Due to the oil conversion, the rear wall of the upright boiler was of course also modified to suit the model.

#8 Second alternator

To meet the increased power consumption, a second alternator was mounted on the boiler.

#9 Lines changed

Some of the pipes on the boiler were partly newly laid or modified.

#10 Large Up-4014 Logo

The pride of the UP team is great. This is why the locomotive even gets a large UP - 4014 logo in the floor of the cab. This logo becomes wonderfully visible on the model when the cab lights are switched on.

#11 Silver axle bearings

The now silver axle bearings on the trailing bogie and tender are very decorative.

#12 Brass valves

The safety valves of the model were made of brass - according to the prototype.

#13 Train radio equipment

According to regulations the prototype was equipped with train radio equipment. The corresponding radio antenna was also added to the model on the roof.

#14 Chalk lettering

Like the very first Big Boy, the resurrected idol #4014 also received the "chalk writing" Big Boy written on the smoke chamber. This writing is of course also present on the model.

To the products


The new Big Boy at Märklin and TRIX

The class 4000 of the Union Pacific Railroad (UP) is certainly one of the most popular among the steam giants of America, if not even worldwide. The concept of the "Big Boy" resulted from the usual requirements as with all other American large locomotive designs: Fewer locomotives should carry heavier train loads at higher speeds.

Basically, the UP procured the 25 locomotives for only one single route: from Cheyenne/Wyoming 830 kilometres westwards through the foothills of the Rocky Mountains via Sherman Hill to Ogden/Utah. The result is a gigantic machine for fast freight transport with a service weight of 548 tons (including tender). In July 1959, the Big Boy era was finally over and the fire in all machines was extinguished.