Train Ferry and Rain

Source: pulsexlb/OpenTTD-patches px-patch (2026-10 batch, pxp-2610.1 – pxp-2610.3), merged into jrpm via git merge.

This batch brings two sizeable new features: the train ferry (ships carrying whole trains) and the rain system (with world darkening and a rain-drop overlay).

Train ferry

Building on the existing Road Vehicle Transport (RoRo), where cars are loaded onto trains, ships and aircraft, ships can now also carry whole trains.

Relation to RoRo

	Road vehicle transport (VEHC)	Train transport (RAIL)
Carriers	trains, ships, aircraft	ships
Cargo carried	road vehicles	trains (locomotives and carriages alike)
Cargo label	VEHC	RAIL
Cargo slot	NUM_CARGO - 1	NUM_CARGO - 2

Both cargo slots sit outside NewGRF's 64 cargo slots, so they never collide.

Loading

• A ship gains the ability to carry whole trains by manually refitting it to the cargo "Vehicles (Train)";
• Loading is per-wagon: a train may be distributed across several cargo holds instead of having to fit into a single hold. This removes the problem of long trains exceeding one hold's capacity;
• The road-sign picker in the transport options now offers train and road-vehicle signs separately, so each kind of transport can declare its own destination;
• The status bar no longer lists the carried vehicles in detail, freeing the space for more important running information.

Capacity display

• The ship info window shows the cargo weight capacity of each hold;
• The train info window shows the capacity of each wagon.

Related fixes

This batch also fixed a number of loading, unloading and platform-reservation defects:

• Ships misjudging track type as incompatible when unloading trains, leaving trains unable to disembark;
• Platform reservations not being cleared when a train boards, plus structural and reservation errors on disembarking;
• Stale platform reservations preventing trains from unloading to platforms again;
• Some platform orientations failing to accept an unloading train;
• The wagon limit on vehicles refitted as transport carriers not being enforced.

Rain system

A purely cosmetic weather simulation that affects visuals only — no gameplay logic or economic values are touched.

Weather presentation

• Random rainy periods: the weather state is driven by a deterministic RNG seeded from the map generation seed, so every player and the server see exactly the same weather;
• Gradual world darkening: the world gradually darkens while raining and recovers when it clears. The darkening steps through RAIN_SHADE_LEVELS levels and is read when drawing viewports;
• Rain-drop overlay: a full-screen rain overlay that scales with zoom to keep the right visual density and carries randomised jitter so drops never look like a static texture.

Options and cheat

• Difficulty option difficulty.rain: decides at new-game time whether rainy world darkening is enabled;
• Sandbox cheat "Weather": a three-state cycle — auto / force rain / force sun.

Savegames

The weather state (whether it is currently raining, the RNG seed, the start of the current rainy period) and the sandbox weather cheat are saved with the game; after loading, the shading jumps straight to the current weather instead of fading in again.

• Chunk: WTHR;
• Feature flag: XSLFI_WEATHER;
• Code: src/weather.cpp, src/weather.h, src/sl/weather_sl.cpp.

Related code

• Train ferry and capacities: src/roadveh_transport.cpp, src/cargo_type.h (CT_RAILVEHICLES), src/table/cargo_const.h
• Rain visuals: src/weather.cpp, src/blitter/32bpp_anim.cpp, src/blitter/40bpp_anim.cpp, src/viewport.cpp
• Weather savegame: src/sl/weather_sl.cpp, src/sl/extended_ver_sl.cpp (XSLFI_WEATHER)
• Settings and cheat: src/table/settings/difficulty_settings.ini (difficulty.rain), src/cheat_gui.cpp, src/cheat_type.h