Every type of vehicle has its own type of Stop.
All what you have to know is trucks cant stop at a Bus or a Tram stop.
Trucks need a special Stop for goods.
Also Busses and Trams cant stop at a truck stop.
In Game there are 3 type of Stops
Bus Stop ( what you also can use for the tram )
Bus and Tram Station there are small were can stop 2 linea at the same time and Big version were can stop 4 linea at the same time.
Truck Stop there are small were can stop 2 linea each 18 goods at the same time and Big version were can stop 4 linea each 16 Goods at the same time.
Bus and Tram share the Stop which are in the game just with one limitation you cant build tram track in a Bus Station.
Train Station and Fright Yards ( Goods Station )
For both of then you can choice between 160 240m and 320 with a maximum of 5 platforms.
For the Railway is the same rule as the bus, tram and truck. You can just pick up Passenger on a Rail station not on a Frigth Yard, also you cant pick up good from a Train Station.
But you can creat a mix train what can carry both passenger and goods but you have to make sure he stop on a Train Station to pick up the passenger and stop on a Frigth Yard to pick up the goods and vice versa.
Here some picture to make it easaier to understand.