Automatic-Transport

Once a market is constructed, auto-transport will be available between cities. Every 2 level improvement to the market will activate an extra 1 transport task. If you want to improve transport speed and capacity, you need to build an airport. Each level improvement on the airport will improve transport speed and capacity.

[ie:Transport Sand Stones]
a)On the street map, you can click the market and then find the auto-transport button. Click it to transport resources to other cities.
b)Select the resource type, destination, and quantity, and then click confirm. 
c)After clicking the confirm button, you will see the transport task being executed (Every 2 level improvement on the market will activate extra 1 transport task).