Trains are very expensive to keep around - You need to exploit the fact that longer lines produce more profit per good moved.
A short line between two cities very close to each other isn*t going to be as profitable as one between two distant cities - This becomes increasingly important as train speeds increase and their maintenance.
A good place to start as far as trains go is usually to find two cities by a river not too close to each other and linking those up with rail. Make a "round the town" line with a few buses or trams to move people to the station (group up the station with a bus stop near it)
Industry is much more complex - You need to complete the entire "loop" to get any production done. If you*re just moving oil to a refinery it is going to stay at 25. If the refinery has the goods moved to nearby cities it will increase production as far as the cities demands go. (usually 50 a town early on)
So something like a Steel line would require 3 trains and a lot of rail early on. Oil would require two and lumber just a single train (Since it can cheat the wagon limitations because Wood and Goods share the same wagon)
As long as you keep the "20 minute or less" transfer limit in mind, trains can be quite profitable. It*s a learning experience - I should know. I have half a day worth of beta videos doing far too short train lines before realizing it was putting me into debt.

大概意思就是火车客运要旅途长，临近的城市无利可图
还有就是保持发车间隔20分钟左右
去试验下，各种摸索

20分钟那个我也看到了，还有老外专门写个帖子，我也不知道他的20分钟具体指什么。是现实世界的20分钟，还是游戏内部的时间。

20分钟的意思就是小人从出发地到目的地所用时间是20分钟以内,小人才会。 和CIM不同的是，如果时间超过20分钟，小人就会宅在家。 所以增加班次和换快车吧