The first problem is probably due to the lower frequency of the train or perhaps the demand in the city you’re delivering to, is already satisfied. Have you tried grouping the station together? Beware that if you do so, all cargo at both stations will be lost. But it may be worth it.
Factories (the ones that produce goods) only expand if they are both recieving and delivering cargo, so in order to achieve factory growth you need to deliver cargo to them and then deliver what they produce to a city. Watch the city demand for goods. Start by only having one line delivering goods from a factory to a city, and when production won’t incrase no more, add another line to another city, and make sure that city has demand for it too. Also check the factorys demands.. need more resources? or need to deliver more goods?
Good luck to you! 🙂