One of the biggest labors of love in city-building games just got even better. The SimCity 4 Network Addon Mod, or simply ‘NAM’ among the community, has long been a de facto recommendation to anyone looking to pick up the classic city builder. It’s a comprehensive overhaul to the game’s transportation and infrastructure networks that combines key fixes with a vast set of additional build pieces such as overpasses, intersections, on-ramps, roundabouts, and so on. It began life just a year after SimCity 4’s 2003 launch. Now, over 20 years later, it’s still going strong with the arrival of NAM update 50.
If you’re still playing SimCity 4 in 2026 (and you should, because it holds up remarkably well, whether you’re there for nostalgia or a history lesson), you’ll probably want to install the Network Addon Mod. The team behind it has just released SimCity 4 NAM 50, and it’s a pretty important leap forward for several reasons. The most significant change is that it’s the first version of the mod to depend on the NAM DLL (Dynamic Link Library), a separate collection of code that you’ll need to manually install alongside it.
The use of the NAM DLL upgrades what the mod is capable of, although it does come with the caveat that you won’t be able to use this latest release on macOS or with old disc editions (the simpler ‘NAM Lite’ version will still run as normal there). The result, however, is that override networks are “much more stable,” and you’ll be able to place down elements adjacent to one another that might previously have needed a one-tile gap between them. Streets can be dragged diagonally, slope tolerances have been improved, and you can build tunnels with the street network.
The new version also includes a fix for the ‘Eternal Commuter Loop’ bug, which might sound fairly innocuous if you’re not deep in the weeds. In actuality, it’s a 23-year-long frustration that has plagued modders ever since launch. Essentially, it’s a problem with the regional pathfinding across city boundaries in certain layouts, causing your Sims to bounce from location to location in search of work without actually taking up a job in any of them. Your zone demand is ruined, traffic builds to unsustainable levels, and the economy falls to pieces before your very eyes.
Until now, the only real solution was to simply avoid building layouts that gave your commuters the chance to loop between locations. Now, by blocking specific neighbor-to-neighbor routes while allowing the rest to run as normal, the problem has been resolved. Elsewhere, NAM 50 cleans up any and all sinkhole-related bugs, improves the stability of roundabouts, introduces some extra intersection layouts, and adds keyboard shortcuts for every network type.
Equally impressively, the mandatory implementation of the DLL has reduced the size of the NAM codebase “by almost 90% and by more than ten million lines, making it easier to maintain and reducing the chance of bugs.” You’ll also notice a “huge” reduction in the time it takes to load your city upon launch, and will no longer need the old 4GB RAM patch that was used in past iterations. If you need some help getting it all up and running, YouTube channel ‘Rob’s Red Hot Spot’ has a handy explainer, seen below.
SimCity 4 NAM update 50 is available to download now. You can find it here, with additional documentation available on its standalone website if you want to learn more about the mod. You’ll need a copy of SimCity 4 Deluxe, or SimCity 4 and the Rush Hour expansion, to use it. Unfortunately, because this is the first edition of the Network Addon Mod to rely on the NAM DLL, it’s now only compatible with digital Windows editions, and not with macOS. The more compact ‘NAM Lite’ package will still work for those versions, however.
It’s an unfortunate caveat, but one that is necessary in order to achieve the benefits that the implementation of the NAM DLL allows. These substantial changes simply wouldn’t be possible without it. “We would like to thank everyone who contributed to testing, feedback, and development of release,” the NAM team writes. “We hope you enjoy NAM 50 and the improvements it brings.”