If anyone wants to know what JGR’s Patch Pack is:

JGR’s Patch Pack, or JGRPP, is a “special” (and I mean that as a compliment) version of OpenTTD created by John G Rennison which includes many new features from QoL improvements to aesthetic fixes to new gameplay mechanics. Some of it’s features have been introduced to vanilla OpenTTD, while others are unlikely to ever be introduced to vanilla due to JGRPP expanding the game in directions that are experimental or too much of a departure from the original game OpenTTD is based off of.

A full list of features should be available in the GitHub repository. Most players into “OpenTTD as a model train set” use JGR’s Patch Pack because without it several gameplay elements mostly used by this subset of players are unavailable. “Casual” and “Infrastructure Spaghetti Network” players will find many features superfluous (if occasionally useful).

Why make a model train set out of the game?

Model trains irl are hella expensive and limited to physically-existent space. Open-world games these days use ridiculous amounts of polygons, which means Voxel Tycoon, even with its’ simplified graphics, is extremely taxing on gaming PCs. NIMBY Rails is comparable but the only available map is of the real world and it’s non-company features (roads, buildings) do not change after the game has started (map is drawn from a snapshot of OpenStreetMap). Simutrans is poorly-documented, leaving players with a steep learning curve. All other transport simulations are either defunct (Bahn, Transport Giant) or extremely limited in map size (Mashinky, Transport Fever 2).

OpenTTD is in many ways the perfect train set for some, and you likely already have what you need to play it at zero additional cost.

Whoa, awesome. I want to try that! Do I need JGRPP to do it?

Not strictly speaking, no. As I said, most of it’s extra features are tailored for a virtual train set, hence it is popular for that usage.

How do I add the Patch Pack to OpenTTD?

That’s the neat part: You don’t need to! Just download the latest release and extract the archive, then rename the folder that results to exclude the extra cruft (e.g. “openttd-jgrpp-0.63.3-windows-win64” -> “openttd”). Make sure to download the win64 version only if your computer has a 64-bit processor, if it doesn’t start up then try the win32 one, and if that fails try the arm64 version. If using a mac, use the mac version (of course). If using Linux, use whichever one matches closest (there are several linux versions, if none of the options specify your distro then use the generic linux version).

Then just run the openttd executable/app in the openttd folder you just made.

Note: One can overwrite the existing files with the contents of a newer archive (e.g. the files in the “openttd-jgrpp-0.63.4-windows-win64” folder can overwrite the files in the jgr “openttd” folder) to update to a new version. No other steps are required to do so.

I have the Steam version of OpenTTD?

Not to worry, OpenTTD was built to be “portable”! …meaning if you download ALL versions of OpenTTD, ensuring you rename the excutables/linux apps to differentiate them, and otherwise merging the folders as-is, you can place the openttd folder (vanilla or jgrpp) on any storage with read/write permissions and the exFAT partition format that has enough space on it. Yes, even an old thumb drive! Then plug it into any computer and double-click the executable/app for the OS of the computer you’re using.

tl;dr? All necessary files are located within the openttd folder in both vanilla and the JGRPP version of OpenTTD. Having it in two places - for example your Steam installation and one on an external hard drive - will consider the other copy (or copies if you have three or more installs) entirely separate from your Steam installation of vanilla OpenTTD.

What if I want to launch JGRPP via Steam?

All mods for this game (NewGRFs, basesets, etc.) are downloadable either online or via the in-game content downloader. There is no Steam Workshop for it. So you could just add it as a non-steam game.

If you don’t plan to play vanilla OpenTTD, you could set Steam to use the latest “beta” archived version (“14.1 - 14.1 release” as of this writing) and overwrite it with the JGRPP files. Since these are archives, they won’t auto-update to overwrite (at least not any time soon) your modified JGRPP Steam install. You can then launch OpenTTD through Steam as normal and it will be the JGRPP install.

What if I use Steam OS/ChimeraOS/Bazzite or have a Steam Deck/“GamerDeck”?

All the above should apply just as well to Steam OS and Linux distros based off of Steam OS. It should work on desktop/laptop and PC Handheld devices equally well too (though you may need a bluetooth mouse).

What if I’m on Android/iOS?

Sadly, there is a lot of issues there…

On Android, JGRPP does not do “official” Android releases. A user named pelya used to do these versions but he has not updated its version base in over half a decade. As of 0.63.3, no unofficial Android release of JGRPP is available.

On iOS, the GPL v2 license is incompatible with the Apple Store’s ToS. A copy has been released, but under false pretenses and illegal circumstances, seemingly by a person or persons from mainland China with the intent to use the game to grift private user data off of unsuspecting users. Apps from unofficial app libraries (Cydia, etc.) are unaccounted for, proceed at your own risk.

Anything else I should know before I try JGRPP?

Compatibility-wise, JGRPP is fully-compatible with all vanilla NewGRFs and downloadable content (as much as is possible in vanilla too, at least). The reverse, however, is not always true. Certain NewGRFs require JGRPP features and will disable themselves in standard OpenTTD. Such GRFs are always clearly labelled and few examples exist; No examples exist of NewGRFs only available on JGRPP at this time, though until OpenTTD 15.0-beta1 the ability to use the JGRPP version of some road stop GRFs was not possible (road waypoints had not been implemented in mainline releases yet and the JGRPP versions included it).

Try reading the “model railroad-izing OpenTTD” guides on the official Discord, they’re likely more helpful than what I can provide.