Mini Metro - The Best Upgrades to Choose to Optimize your Metro System

Date: 2024-03-27 | create | tech | video-games | mini-metro |

Mini Metro is a simple game that is hard to master. Picking the right upgrades from start to finish is crucial for placing high on the leaderboards.

I've previously shared my Simple Scalable Systems for consistently hitting the top 10% on Mini Metro leaderboards and here we'll dive into the best upgrades and when you should choose them.

When to Choose each Upgrade

The right upgrade to choose is largely dependent on the state of your game - what your metro system looks like and what bottlenecks it has.

In general you want to choose the upgrade that best fixes:

  • A current bottleneck
  • A near-future bottleneck

This greedy system allows you to best optimize for real problems and not waste upgrades on imaginary ones. (i.e. don't choose anything cause you might need it later, only if you do need it now / next)

My general heuristics for choosing from the available upgrades are as follows:

  • If no clear bottleneck better solved by others -> default to carriage to improve carry capacity
  • If specific lines are backing up / don't have 2 free lines -> choose a new line
  • If no free crossings -> get crossings
  • Interchanges -> Never
  • Special trains -> depends

Next we'll dive into each upgrade and what they're good for.

The Best Default Upgrade - Carriage

Carriages are the best overall upgrade and thus the best default if no better choice. They are the only upgrade that allows you to consistently improve carry capacity of a line. They effectively double the carry capacity you get for that week - increasing it from 6 (1 train) to 12 (1 train + 1 carriage).

Carry capacity will always be the limiting factor in a game so this will always be useful no matter where you are in a game.

Another hidden benefit is that carriages have a different max per line than trains. This means even when a line is maxed out on trains you can still add carriages to increase its capacity. (Max trains per line varies but typically is between 4 and 6 via r/MiniMetro)

When to pick a carriage: If you don't have a specific, urgent bottleneck better served by another upgrade -> default to carriage.

The Regular Upgrade - New Line

Lines are the most important upgrade so you need to regularly choose them. They allow you flexibility to draw new routes which is necessary to make your system more efficient.

That said, Lines should not be your default choice as you'll often find equilibriums in early / mid game where new lines aren't useful. For those times picking a different upgrade that better prepares you for current bottlenecks is often a better bet.

My general rule of thumb is:

  • Always have 1 line free for the Ghost Line
  • Try to have 1 extra line free so can draw a new route / restructure system when needed
  • ~never have more than 2 lines free because it's not useful

By regularly acquiring new Lines when needed (but not choosing them every time) you'll have a good balance of maxing your system optionality without having underutilized resources in your inventory.

The Insurance Upgrade - Crossings

Mini Metro maps often have various water features that require crossings (bridges / tunnels) for lines to be drawn over them. This constrains the types of lines you can draw as you are limited in how you can connect stations across these water features.

Like lines, having too many crossings is not useful as there's nothing you can do with the extras but having too few is deadly and can lead to a quick game over.

My rule of thumb:

  • Always have 1 crossing free for the Ghost Line
  • Have 2 more free if bottlenecked on an area across water so you can refactor it with a line

Having a few extra crossings is a good insurance policy against an unlucky station popping up across water and ruining your game.

The Useless Upgrade - Interchanges

Interchanges are mostly useless. This is because they don't help you remove shapes from your system, they only serve to better hold them. It's kind of like moving food around on your plate - the food doesn't disappear, it just gets messier.

It's a much better investment to choose the other upgrades that help remove shapes from the system more efficiently.

I only choose Interchanges if the other upgrades are even more useless - like if I already have too many crossings.

The Unique Upgrade - Map-Specific Upgrades

Some maps have unique upgrades like the fast train on Osaka. Choosing these is highly dependent on your own play style, the map, and the state of your system so I don't have much advice for these aside from try them out and see if you like them.


That's generally my Simple Scalable System for picking upgrades in Mini Metro.

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