Space Age Railway Expansion: Nuclear & Fusion Trains + Rolling Stock

Not another vanilla train reskin. This has real new graphics and train model

Space Age Railway Expansion extends Factorio's railway progression into the late game with a dedicated Nuclear Locomotive, five Fusion Locomotive tiers, higher-capacity cargo and fluid wagons, upgraded storage tanks, Custom Mk1 & Mk2 Train Roboports, new propulsion fuels, new technologies, native upgrade progression and configurable graphics.

The aim is to make railway technology continue progressing alongside the rest of Space Age instead of leaving the vanilla locomotive and rolling stock as the final step.

Emissions are still a work in progress, still trying to get the best out of the game.

Main Features

• Dedicated Nuclear Locomotive unlocked with Nuclear Power
• Fusion Locomotives Mk1 through Mk5
• Increasing Fusion locomotive power, speed, braking and technology cost by tier
• Dedicated Nuclear Propulsion Cell
• Dedicated Cooled Fusion Locomotive Cell
• Spent Fusion Locomotive Cell recovery and reprocessing
• Productivity support for Nuclear Propulsion Cell and Cooled Fusion Locomotive Cell production
• Kovarex Axial-Flux Motors used in Fusion locomotive construction
• Cargo Wagon Mk2 and Mk3
• Fluid Wagon Mk2 and Mk3
• Storage Tank Mk2 and Mk3
• Fluid Pumps Mk2 and Mk3
• Nuclear/Fusion Mk/Cargo wagons Mk/Fluid Wagons Mk* each have their own Minimap Icons
• Mk1 & Mk2 Train Roboports - More powerful than regular. Consumes Train Fuel for power.
• Dedicated High-Capacity Logistics Mk2 and Cryogenic Logistics Mk3 research
• Native Factorio Upgrade Planner progression for Fusion locomotives
• Optional direct conversion recipes between enabled Mk levels
• Equipment grids for Nuclear and Fusion locomotives
• Configurable Exoskeleton limits
• Enable the tiers you want for locomotive, cargo wagons/fluid wagons and storage-tank tiers via mod settings
• 256-direction Fusion locomotive graphics
• Standard Detail and optional High Detail Fusion locomotive graphics
• No continuous locomotive on_tick polling

Locomotive Progression

Nuclear Locomotive

The Nuclear Locomotive provides a dedicated fission-powered railway stage and is unlocked with Nuclear Power.

It uses a heavier 3000-weight chassis, a dedicated Nuclear Propulsion Cell and its own fuel category. It is intentionally separate from the Fusion Mk upgrade chain.

When a Nuclear Propulsion Cell is fully consumed it produces a depleted uranium fuel cell in the locomotive's burnt-result inventory.

Fusion Locomotives

Fusion locomotives provide the main late-game performance progression:

• Fusion Locomotive Mk1
• Fusion Locomotive Mk2
• Fusion Locomotive Mk3
• Fusion Locomotive Mk4
• Fusion Locomotive Mk5

All five Fusion tiers use a 3000-weight chassis. Higher tiers increase maximum power, base top speed and braking force while intentionally reducing burner effectivity as a balance trade-off for the additional performance.

Locomotive Performance

The figures below are the current mod values. By default only Fusion Mk1 is enabled, update the mod settings for better versions.
I did not want this to be a grind for quality, so I created dedicated versions with marked improvements. Only fuel Quality adds another peformance lever.

Fuel runtime is calculated at continuous maximum power. Trains throttle fuel use once they reach speed, so normal route endurance can be longer than these minimum/max-load figures.

The Nuclear Propulsion Cell has an 8 GJ nominal fuel value and stack size 5, so one fully loaded fuel slot can hold five cells.

The Cooled Fusion Locomotive Cell has a 15 GJ nominal fuel value and stack size 2.

Cooled Fusion Locomotive Cell Quality Performance

Cooled Fusion Locomotive Cells support Factorio quality.

Fuel quality increases acceleration and top-speed multipliers. The locomotive Mk itself remains the performance tier, while fuel quality provides an additional performance upgrade.

Fusion Trains Top Speed Fuel by Quality

Mk1 & Mk2 Train Roboport

Train Roboports — Experimental

Train Roboports Mk1 and Mk2 add train-powered construction coverage to Nuclear and Fusion trains. Install a single Train Roboport Controller in an eligible locomotive equipment grid and the mod automatically equips each supported cargo wagon (Vanilla Cargo wagons, Mk2 & Mk3 are all supported) with its own construction roboport and Train Power Link generator (up to 12 cargo wagons). Each wagon uses the construction robots, repair packs and building materials stored in that wagon’s own inventory.

Because Nuclear and Fusion fuel cells contain extremely high amounts of energy, Train Roboports recharge from the train’s propulsion fuel only while stopped in an approved service state. The system will never drain the train below its protected fuel reserve: Nuclear retains 3.2 GJ of active fuel plus one untouched 8 GJ spare cell (11.2 GJ total protected reserve), while Fusion retains 12 GJ of represented fuel energy. A recharge only occurs when the full required amount can be supplied without crossing these limits.

Mk1: 60×60 construction area, 10 robots, 8 charging ports / 8 MW.
Mk2: 80×80 construction area, 25 robots, 12 charging ports / 12 MW.

The system is fully event-driven and does not continuously scan trains while they are travelling.

• While driving the train in manual mode. If the train stops will trigger a recharge cycle
• Train in Automatic mode. If the train stops at a station it will trigger a recharge cycle
• While train in Automatic mode, it will not initiate a recharge cycle waiting at signals OR stuck due to pathing or station train limits

Mk1 Train Roboport - Mk2 Train Roboport -

By Default this is turned off in the mod settings. I have extensively tested all the conditions and events and happy it works as expect, I just not had the time to use it throughout a full playthrough yet so its possible there is some kind of edge case I not account for. for that reason I tag this experimental

Dedicated Fuel Cells

Nuclear Propulsion Cell

The Nuclear Locomotive uses a purpose-built Nuclear Propulsion Cell manufactured in a centrifuge.
Its performance is the same as vanilla but has a higher top speed and less of a need to refule due to the density of the fuel. As with all trains in this mod it has has an Equipment Grid.

Current fuel characteristics:

• 8 GJ nominal fuel value
• Stack size 5
• 2.50x vehicle acceleration multiplier
• No additional top-speed multiplier
• Normal quality only
• Produces a depleted uranium fuel cell when consumed

Cooled Fusion Locomotive Cell

A normal Space Age Fusion Power Cell cannot fuel a Fusion locomotive directly. It must first be prepared with cold fluoroketone for locomotive use.

Current fuel characteristics:

• 15 GJ nominal fuel value
• Stack size 2
• Normal quality acceleration multiplier: 3.00x
• Normal quality top-speed multiplier: 1.20x
• Additional acceleration and top-speed bonuses from higher fuel quality
• Produces a Spent Fusion Locomotive Cell when consumed

The spent cell can then be reprocessed to recover the coolant as hot fluoroketone.

Upgrade Planner Support

Allows upgrade of vanilla to nuclear or any of the fusion trains.
It cant be an empty upgrade planner it has to be set like below. This prevents accidental upgrades.

Any items in trains with equipment grids will persist after the upgrade. On the upgrade request, they are stored and then restored when the new upgraded train is placed. Its keeps the items, their position, and their charge as it was before the upgrade.

Fusion Research Progression

Fusion Locomotive Mk1 follows Space Age Fusion Reactor technology. Each higher Mk requires the previous Fusion locomotive technology.

Fusion Reactor
    |
    +-- Fusion Locomotive Mk1   2,000 science units   60 s/unit
          |
          +-- Mk2               3,000 science units   80 s/unit
                |
                +-- Mk3         4,000 science units  100 s/unit
                      |
                      +-- Mk4   5,000 science units  120 s/unit
                            |
                            +-- Mk5   6,000 science units  140 s/unit

Agricultural science is deliberately removed from the copied Fusion Reactor science-pack set for these locomotive technologies.

Each research uses the matching Mk locomotive icon.

More Technologically Advanced Motor Requirement- Kovarex Axial-Flux Motor

Fusion locomotives require a dedicated high-performance traction component: the Kovarex Axial-Flux Motor.

Motor requirements increase with each tier:

• Mk1 - 20 motors
• Mk2 - 30 motors
• Mk3 - 40 motors
• Mk4 - 50 motors
• Mk5 - 60 motors

All Fusion locomotive full-build recipes are produced in the Cryoplant and use Space Age materials rather than simply scaling the vanilla locomotive recipe.

Fusion Train Ingredients

Mk1

Higher-Capacity Rolling Stock

Quality Capacity Scaling

When the Quality expansion is active, higher-quality Mk2/Mk3 rolling stock and storage tanks gain additional storage capacity.

Colours Based on Materials Used. Mk2 Tungston Mk3 Tungston & Fluoroketone Alloy

Additional Mk2 & Mk3 Pumps

Tanks and trains can now carry so much fluid getting them out the train was taking too long to unload. Now added Mk2 and Mk3 pumps.
Like vanilla, quality does increase their performance. I scaled their pumping speeds in line with the increased fluid tanks and fluid cargo wagons.
Meaning when using their respective versions should empty or load in the same amount of time.

Logistics Research

High-Capacity Logistics Mk2

Unlocks the enabled Mk2 versions of Cargo Wagon, Fluid Wagon and Storage Tank together with their enabled direct-upgrade recipes.

Cryogenic Logistics Mk3

Unlocks the enabled Mk3 versions and Mk2 -> Mk3 direct conversions.

Cryogenic Logistics Mk3 requires both High-Capacity Logistics Mk2 and Cryogenic Plant progression.

The technology prototypes are settings-aware: if only some Mk2/Mk3 extension families are enabled, the research unlocks only the enabled content.

Direct Upgrade Recipes

Optional direct-upgrade recipes allow existing railway equipment to be converted into a higher enabled tier while paying the missing upgrade materials.

Fusion Locomotives support every enabled lower-Mk -> higher-Mk permutation.

With Mk5 enabled:

• Mk1 -> Mk2, Mk3, Mk4 or Mk5
• Mk2 -> Mk3, Mk4 or Mk5
• Mk3 -> Mk4 or Mk5
• Mk4 -> Mk5

Cargo Wagons, Fluid Wagons and Storage Tanks also support their configured base -> Mk2, base -> Mk3 and Mk2 -> Mk3 conversion paths.

Direct upgrade recipes are enabled by default and can be disabled in Startup mod settings.

Equipment Grids

Nuclear and Fusion locomotives include equipment grids.

A Startup setting controls the number of Exoskeletons allowed in the locomotive grid:

• Disabled
• Maximum 1
• Maximum 2
• Maximum 3

Toolbelt equipment is always blocked.

The supported Fusion Mk upgrade path preserves installed equipment when locomotives are upgraded.

Minimap Icons

Nuclear / Fusion Mk1-5 / Cargo wagons Mk2-3 / Fluid Wagons Mk2-3 each have their own Minimap Icons

Custom Fusion Locomotive Graphics (Not a reskin)

The Fusion locomotive uses a custom high-detail model rendered specifically for Factorio.

The production graphics use 256 rotational directions, giving smooth directional transitions around curves while retaining Factorio's normal rolling-stock behaviour.

Standard Detail (SD)

The default graphics mode same resolution as vanilla train but with our own custom model.

High Detail (HD)

The optional High Detail mode uses 948x916 BODY which is x2 the detail of vanilla.

HD is estimated to use approximately 1.24 GiB additional VRAM compared with SD.

LIGHT and SHADOW remain shared between SD and HD.

The VRAM figure is a planning estimate. Actual runtime usage can vary with texture handling, graphics settings, mipmaps, other mods and installed hardware.

Mod Settings

Configuration is available under:

Settings -> Mod settings -> Startup

Train Roboports

• false - Default
• True

Fusion Locomotive Maximum Mk

• Mk1 only - Default
• Mk1-Mk2
• Mk1-Mk3
• Mk1-Mk4
• Mk1-Mk5

Cargo Wagon Maximum Mk

• Disabled
• Mk2 - Default
• Mk2 + Mk3

Fluid Wagon Maximum Mk

• Disabled
• Mk2 - Default
• Mk2 + Mk3

Storage Tank Maximum Mk

• Disabled
• Mk2 - Default
• Mk2 + Mk3

Fusion Locomotive Graphics Detail

• Standard Detail (SD) - Default
• High Detail (HD)

Nuclear Locomotive

The Nuclear Locomotive can be enabled or disabled independently.

Direct Upgrade Recipes

The convenience/direct-conversion recipe family can be enabled or disabled.

Exoskeleton Limit

Controls how many Exoskeletons may be installed in Nuclear and Fusion locomotive equipment grids.

Credits

• 3D locomotive model and commissioned hard-surface artwork: Janiru Semitha https://www.fiverr.com/janiruisawesome?source=gig_page
  I am not good with graphics so I paid for a graphics designer to bring the model to life. You want any similar work please reach out to him.

Please do not extract or reuse the mod's graphics, icons, textures, rendered locomotive assets or 3D/source artwork in other projects without permission. See the mod's custom license for the full terms.

Why Use This Mod?

Space Age Railway Expansion is intended for players who want railway technology to continue evolving alongside the rest of the Space Age factory.

It adds:

• A meaningful Nuclear railway stage
• A five-tier Fusion locomotive progression
• Higher late-game train performance
• Dedicated Nuclear and Fusion propulsion fuels
• Higher-capacity Cargo and Fluid Wagons
• Higher-capacity Storage Tanks
• New late-game railway/logistics technologies
• Upgrade paths for existing rolling stock
• Configurable content tiers
• 256-direction locomotive graphics
• Optional High Detail graphics

The goal is not simply to reskin the vanilla locomotive. It is to provide a complete late-game railway progression for Space Age.