So I designated Huainan as the center of my railroad empire - being the larger one and more in central position -, so I built the maintenance buildings there, since for now all the trains I wanted to run would go through there. Roundhouse, water and sanding towers. Every engine needs water, sand, and oil (which represents maintenance), and these three buildings provide that. Even if a train doesn't stop just passes a station with these will receive these stuff. I also built a post office both here and at Xuzhou.
Almost perfectly level tracks, from 0,0 to 0,5 grades. A bit more turns what I would prefer, but they ain't sharp at least so little slowdowns for the trains.
My first train became a passenger one, the settlements on this map provides customers abundantly.
The second engine will haul mail. That 4-4-0 American-C is breddy gud engine. It will be main workforce for a while for all lines.
Couple of things to consider when buying a new engine. It's price the least important stat I think, coughing up that one time fee is dwarfed by everything else. Even the maintenance and fuel costs are something just needs to be swallowed for a good engine. What really is important is how frequently the engine will break down, and how quick it can reach it's destination - here comes the acceleration and top speed comes in the picture.
Speed is influenced by the grade of the track, how fast it can run on uneven terrain, up on slopes - tugging how much weight. Some trains might be quick, but given enough load, they might struggle uphill, while a slower engine could easily pass it by. I guess it's torque or sumtin. This little chart allows the player to check the top speed on different grades, while pulling 1 to 6 cars, with a load weight that can be set (incrementing/decrementing by 5 tons). Passengers and mail weighs 15 tons.