The built up is absolutly insanely incredbily, but at the same time, you got to be honest and consider that Chengdu has a population of nearly 21million, whereas Tronto is at about 3million. Toronto also has a larger tram network then Chengdu. If you would compare it to a large European city, you also have to consider regional rail. Chengdu has no regular train station closer then 5km to the city center.
Again it is insane how quickly China builts metros, but metros are not the only viable form of public transit.
Remarkably similar design, a ring route with routes coming out in all directions. In Berlin the rapid transit trains are more focused in the middle and only really diverge at the ring with metros covering most of the space. While in Chengdu the trains don't share a rail, (except for the airport service) and have longer branch lines.
The regional trains (thin red lines on the map) in Berlin go through the center similar to the rapid transit and make a few stops along some of the branch lines and the high speed rail only stops at the main station and one major station in each cardinal direction (marked with the train in a yellow circle).
