Quick answer
Towns grow by earning XP when your passengers and cargo reach their final destination in the town.[1] How fast they grow depends on two ratings. Supplies is how well you serve passengers and cargo. Authority is the lowest of six ratings, so always fix the weakest one first.[1] There are 18 town levels. The game does not cap city size, but very large cities can hit your CPU's limits.[2]
The 18 town levels
Levels run from Level 1 Small Hamlet through Hamlet, Large Hamlet, Small Village, Village, Large Village, Small Town, Town, Large Town, Small Suburb, Suburb, Large Suburb, Small City, City, Large City, Small Metropolis and Metropolis, up to Level 18 Large Metropolis.[1]
"A town needs 1,000 total XP to reach level 2". Each later level-up needs 1.5 times the XP of the previous one.[1] That makes the next steps 1,500, then 2,250, then 3,375 XP (our calculation from that rule).
Where XP comes from
Final XP = raw XP × XP multiplier.[1]
| Arrival | Raw XP |
|---|---|
| Passenger from the same town | 5 |
| Passenger from a neighboring town | 10 |
| Passenger from a town farther away | 20 |
| Cargo item, least complex types | 10 |
| Cargo item, next complexity level | 20 |
| Cargo item, most complex types | 40 |
Your headquarters adds a growth bonus that starts at 5% and rises as you expand it.[1] Practical takeaway: longer passenger trips between towns and more complex cargo earn the most XP per arrival.
The ratings that set your multiplier
Supplies is the average of two scores:[1]
- Passenger supplies: based on how many residents use public transport. 50% line usage gives the maximum.
- Cargo supplies: the best-served district's cargo rating.
Authority is the lowest of these six:[1]
| Rating | What moves it |
|---|---|
| Reputation | Landscaping, removing town buildings and cutting main connections lower it. Celebrations and marketing raise it. Replanting trees recovers what tree removal cost. |
| Happiness | Waiting times at stations and travel time |
| Delivery | Cargo arriving on time. Late cargo still pays in full but hurts growth. |
| Traffic | Congested streets |
| Noise | Noise in residential areas |
| Pollution | Pollution across the town area |
Each rating has a matching data layer (passenger satisfaction, cargo satisfaction, traffic, noise, pollution) that shows where the problem is.[1] A developer blog adds that for longer journeys "it may be worth investing in faster or more comfortable vehicles".[3]
New cargo demands as towns level up
A town starts with one cargo demand in each of its commercial and industrial districts, and adds more as it levels up:[1]
| Town level | New demand |
|---|---|
| 5 | Second commercial demand |
| 7 | Second industrial demand |
| 9 | Third commercial demand (may be a most-complex cargo) |
| 11 | Third industrial demand (may be a most-complex cargo) |
See industries and cargo for which goods each district buys.
Is there a maximum city size?
No hard cap. The official troubleshooting page says Transport Fever 3 "doesn't limit city sizes or number of towns". However, every resident is simulated with their own trips to work and shopping, which "may sooner or later exceed the power of your processor".[2] For reference, the Megatropolis achievement asks for one town of at least 3,000 residents, and Populated Country for 50,000 residents on one map (achievements).[4]
