UP Steam Excursion Overhaul Pack

In the 1920s, the railroad mentality of moving freight with no concern for how long it took was in decline. Competition from trucking meant railroads would need to upgrade infrastructure, and rapidly innovate steam technology to decrease costs while also increasing tonnage and speed.

The Union Pacific was one such railroad ready to shift to this new era of railroading. Previous steam locomotive designs, such as their 2-8-8-0 ‘Bullmoose’ Mallets and 2-10-2 TTT series locomotives, with small 57 and 63 inch drivers respectively, weren’t quite up to the task. The Mallets, while powerful, were too slow for modern standards, and their bulky front engine set, powered by low pressure steam, hammered the rails much more than traditional simple expansion locomotives. Contrasting with the Bullmooses, the TTTs were slightly faster, but their lower power output and less than ideal speeds still hampered their potential, especially on the Overland’s steeper grades.

From 1925 to 1930, UP would experiment with 3 cylinder locomotives, such as their 4-10-2 ‘Overland’ and the unequaled 4-12-2 9000 Class locomotives. The 9000s especially proved themselves as being reliable workhorses on the plains of Nebraska, with improved fuel economy and speed, and comparable pulling power to the Mallets, but their stiff-legged nature were much less versatile on winding mountain tracks, and the internal 3rd cylinders were a major nuisance for shop crews.

Years of experience with all sorts of locomotives led their motive power department to design a new articulated locomotive. With its 69 inch drivers, enlarged firebox held up by a 4 wheel trailing truck, 4 high pressure cylinders, and roller bearing equipped axles, this new 4-6-6-4 type locomotive – classed the CSA-1 – made for an impressive and modern steam locomotive poised to challenge conventions, and was first put to work in 1936 throughout the UP’s vast system.

Despite their impressive stats, the ‘Challengers’ still struggled on the eastbound 1.14% climb from Ogden to Wahsatch, Utah, especially with 3000+ ton trains, necessitating helper service, not ideal for increasing speed nor decreasing costs. In 1941, UP would yet again defy traditions and come up with a new wheel arrangement; the 4-8-8-4 type.

Nicknamed the ‘Big Boys’, the 20 locomotives of the first order lived up to their name. Although not quite the largest, most powerful, nor heaviest, they were highly successful and user friendly, well regarded by most who worked on them, though not without fault. Their striking appearance made them an iconic symbol of the rails from Ogden to Green River, Wyoming, their original operating range. Eventually, their territory was expanded to Laramie and Cheyenne, Wyoming, and by some accounts they made occasional runs to Colorado and Nebraska.

The 4884-1’s exceptional performance eventually led to an order of 5 more Big Boys, and a new Challenger design (sometimes called heavy, late, or Jabelmann Challengers), based on the Big Boys.

While freight service was of high importance for the railroads, passenger trains also necessitated improvements. 4-8-2 ‘Mountain’ types, widespread on UP passenger trains, were also showing their age by the mid 30s. Using similar design principles as the first 2 orders of Challengers, UP’s new 4-8-4 locomotives of the FEF series of 1937, would become a mainstay on crack passenger trains, and also ushered in a new era for the railroad, with more modern gothic lettering and a tender roadname and cab numbers (opposite to what it was before).

3 classes of FEFs were built: the first, FEF-1s (800-819) had an overall smaller profile compared to the following FEF-2 and FEF-3 classes, extending to their drivers (77 vs 80in), tender (3 axle bogies vs 4-10-0 centipede type), cylinders and tractive effort. The centipede tender design, originating with the FEF-2s in 1939, was used on all following UP locomotive designs.

The Big Boys, Challengers, and FEF series were the best steam locomotives ever used by the Union Pacific. Throughout their carriers, they received frequent upgrades and changes, and were often subjects of performance improving experiments and enhancements, with all FEFs and 18 Challengers being equipped with ‘Wind Wings’ and also successfully converted to oil burning, and though both changes were trialed on Big Boys (4019 and 4005 respectively), they were temporary as they weren’t as successful as the former 2.

Big Boy 4005 was also unfortunately involved in a serious derailment, fatally wounding all three men in the cab, and a few livestock from its train, owed to an inexperienced worker failing to warn the incoming train of a divergent switch.

In 1959, the last breaths of UP steam were taken, when the last Big Boys and Challengers were tied down after making their final runs, and all of the steam locomotives were retired – except one.

FEF-3 844, the last steam locomotive delivered to the Union Pacific, was kept in service at Cheyenne for snow melting experiments, when UP realized the benefits of a steam powered, public relations program, and kept 844 in service. The big 4-8-4 ‘Northern’ type locomotive has made excursion runs since the early 60s, either solo, meeting or doubleheading with other famous excursion locomotives. UP 3985, a late Challenger, was restored to operation in 1980, and made several excursion runs until 2010, being the largest steam locomotive in operational condition until Big Boy 4014 took its place in after restoration in 2019.

Other than these locomotives, 7 other Big Boys 1 other Heavy Challenger, one FEF-1 and one FEF-2 survive, with another FEF-3 used as spare parts for 844. To this day, all 3 classes have a large and diverse fanbase, from people who just like big trains, to those who see them as the pinnacle of human engineering.

UP 4884-1 (Design white lining, design black lining, rebuilt black lining, excursion)
UP 4664-4 (DWL, DBL, RBL, Two tone gray, Greyhound)
UP FEF-3 (DWL, DBL, RBL, TTG, GH, EX, EXGH)
UP 25-C/23-C Tenders (WL, BL, TTG, GH)

L | Main Light
Shift + L | Cab light | Backup light [Tender]
L+1 | Markers

Shift+1 | Aftercoolers [4884-1], Mars lamp [FEF-3] | Bunker extension [Tenders]
Shift+2 | As built dynamo [4884-1] | Stoker engine housing [Tenders]
Shift+3 | Double dynamo [4884-1] | Top toolbox [Tenders]
Shift+4 | PTC dynamo [4884-1] | PTC box [25-C Tender]
L+2 | Wind Wings
L+3 | Stack hood [4884-1, 4664-4], Mars light [FEF-3]
L+4 | Swinging Pilot
L+5 | Default dynamo [4884-1], Dynamo swap [4664-4, FEF-3]
L+6 | Mechanical Lubricator [4884-1]

All items have livery support. Feel free to make liveries with these mods, however, please do provide a link to the original mod, and don’t just reupload them without making modifications or claim them as your own.

Liveries using templates from older versions of these mods are not compatible, since these use entirely new meshes with more details and different proportions, you will have to tweak several things or start from scratch to fix any issues.

Hello! Sorry for the wait, but I got a bit bored and burnt out of modeling for a bit. Since the 2 year anniversary of my 3rd UP workshop item was coming up, I decided to upload yet another one, mainly to fix the old, terrible models, by making new ones from scratch, which would break a lot of liveries had I updated the original versions. 3 of the locomotives from that pack are missing, as well as the auxiliary water tenders, and I have also found a few high quality folios of some underrepresented UP power, so this is by no means the last UP steam pack either. I also want to update more old and terrible mods I’ve made, but no promises as to when that happens. Stay safe y’all.