·If you build a tunnel from one side of the world to another you can make billions! ·Delete a piece of straight road owned by the opposition by building a level crossing on it. Now you own the land, and can delete it! ·To crash the trains of the opposition companies, do the following:
. Build a depot (a) so that it joins on to An oppositions station, and build the cheapest possible train in the depot. As soon as a train arrives at the station, start up your train, tell it to ignore signals, and - BOOM!
Where possible always build your railway tracks over the opposition's roads. If a train smashes into a road vehicle the road vehicle will be destroyed, but the train will continue unhindered. Likewise never build a road over a railway track to protect your road vehicles! ·If you build two or more different station types adjacent to each other, then they all become classed as one station, drawing from a pool of passengers and goods. This is great for saving yourself from having too many stations later in the game. ·"When you have reached the stage when you can't build anymore vehicles, because you have too many, but still want to use the 155mph Eurostar engines on a full train, if you build nine of the wagons that you want to use, and you can only build one more vehicle because you have too many, build a Eurostar train and only the front engine will be built, the train will consist of nine wagons."  ·"Here are a few little hints that will really get on the computer opponents nerves: Find one of their main roads which has a lot of their traffic on, build a depot and a few lines of tracks to cross the road and set the cheapest train (with some carriages on) trundling along. Then stop that train when it fully blocks the road.This V. Annoying.
Build trees around your rail station that is near to an opponents. The people will think yours is nicer so they come to your station.
Build a road depot on your opponents main road and set some really old bangers along it. They will break down continually and cause a big traffic jam.
If you feel that you have a bit more cash, you can try picking off the opponents road vehicles. Do the same as you do for the road block cheat but with an express train and lots more track. When it does crash, the train survives but the lorry or bus doesn't." 

·If the opponent is growing cash like grass, and you have some pounds to spare, do the following thing: If the opponent has built a timewaisting and very long route for a group of cars, you can make a piece of road that turns out of his road when it bends, make a good piece of shortcut for the cars, and join the shortcut up with the road again. Normally, the lorries or buses chose to drive on the shortcut you made for them, and when as many as possible drive on the shortcut, remove or bulldozer each end of it. The cars are now trapped, and the owner will only loose money in having them driving about."  That's all the hints that I have for now, but I hope to get some more as soon as possible.