Part 2: The Game's Artificial Intelligence
Why is it so poor?
One of the weakest aspects of TT is its AI (Artificial Intelligence). The same could be said for almost any game, but it's particularly easy to outwit the AI in TT.
Examples of AI stupidity
Here is a classic example:
When building an airport, the AI is allowed to bulldoze, raise, and lower the land around a town for free, and without hurting its Local Authority rating. Human players certainly don't get this luxury! Even with this advantage/cheat, the AI still places airports in horrible locations.
Ask the programmer
Why is the AI so inept at designing layouts? Some time ago I asked Chris Sawyer about this by email, and he responded:
The reason for this is that the computer-run companies build their tracks dynamically. What I mean by that is that they assess the terrain and possible actions at the instant they are about to build a section of track, rather than designing an entire route before constructing it. The route designs could have been much better if they had been planned in advance, but planning the route in advance assumes that the terrain won't change before the route is entirely constructed. As I wanted the rival companies to build slowly, section by section, just like the 'human' player, there was a very high possibility that a planned route would fail because part of the terrain had changed (ie. a house had appeared, ground lowered/raised, road extended etc.). It would also make it very easy for the human player to 'foil' every computer attempt at a decent route, as the human player could watch the computer-run company start to build a route, then lower or raise just one block of land in the way. The computer-run company would then have to remove all its track and start again from the planning stage.That pretty much sums everything up.
The dynamic algorithms I used for the computer-run companies can perform very well given the right terrain, but given the limitations of a hilly terrain and an urban area they often just cannot work out how to build a decent route. That's the difference between a human and a computer - a human can look at a route construction problem and quickly see the best way to link two points using experience and knowledge, but a computer has to calculate the same problem using simple rules and searches. The rules and recursive searches used in Transport Tycoon can be very effective given enough chance - if allowed to recurse to a level of about 100 the computer would build very efficient railway routes. Unfortunately, each decision by the computer would take several days to calculate at that level, so the recursion (or look ahead level) was set at about 6 to keep the speed up. Increasing the recursion level to just 10 produced decisions that took several seconds to perform - not what you need in a game that needs to run at 10 frames per second or faster.
How do I beat it?
Defeating the AI is extremely easy when using legitimate methods. Simply make a lot of money and buy the opponents out. But, if you don't like to use legitimate means, there are a clever techniques (also called cheats) that you can use to harm the computer's companies.
Kaboom!! The truck is wrecked, and the ratings of the rival's nearby stations fall to near zero! However, your ratings are unaffected. Repeat this until all of the road vehicles on the opponent's route are destroyed. Then, after a month or so, the computer will close the stations on that route, and it will be all yours for the taking!
The hard part is coaxing them onto your own roads. Since the rival's roads tend to be laid out horribly, you should try to build a better, shorter road between the rival's stations. Road vehicles always utilize the shortest route, so they will use your road instead! Destroy both ends of the road when the rival's vehicles are on it, and voila!
Unfortunately, in doing this you lose use of the train, and its value decreases. But, in fact, you don't actually need a train permanently parked there. Have your train head towards the grade crossing. The instant the flashing lights come on, reverse the train. If timed perfectly, this maneuver will result in the flashing lights staying on indefinitely, even after the train is miles away. The trucks still won't be able to cross, but you don't have to park your train there!
|Build a depot at the end of the rival's station. Build the cheapest train you can in the depot. Then, when the rival's train comes into the station, order the train to move forward and to ignore signals. Then...|
The rival's train is destroyed! Unfortunately, so is yours. Beware, the ratings of your nearby stations will plunge to near zero. The rival's ratings will remain unchanged (darn!). You must wait until the remains of your train are hauled off to the scrap yard before you can bulldoze the depot.
|Build a rail line out from the end of a rival's station. Build roads (grade crossings) on all squares. The AI will think it own these squares, so instead of turning around, the rival train will travel ahead on the rails! When the train reaches the end, destroy the track between it and the station, and it will be trapped!|
Now the train will go nowhere fast, and it will still cost the rival to maintain it! Unfortunately, this only works with stations that have free space behind them. Also, because you need grade crossings, you can't curve these rails.
|The picture shows two trains colliding with each other. The red train (top left) collided with the green train (lower left) which was parked in the station. The ratings in the red company's nearby stations dropped to zero but the green's remained the same. As soon as the rubble was cleared away, both companies shut down these stations.|
Note: In the above picture, the red train would not have be able to enter the green station, and vice-versa. If both stations were owned by red, then the red train could cross over to the other line. If you deleted the connection, that red train would be trapped in the other line and would lose money and risk a collision with the other red train. Make sense?
|Build a rail line from the back of the depot to the end of the station as shown in the picture. A bug in the way TT handles depots will make it think that your rails are owned by the AI, causing the signal system to malfunction. When a train comes near the station, the signals will turn red, so the train has no choice but to go to the depot.|
Paradoxically, it's the train itself that causes the signal to turn red. In effect, the train is trapping itself! After entering the depot, the train will be forced to backtrack the way it came, away from the station! The train won't ever make a profit, but the AI will still have to pay maintenance for it.
How do I make it more challenging?
Choose these difficulty settings to make the AI more competitive:
Oddly enough, harder settings hurt the AI just as much (or more) as the human player. See the section on difficulty settings for more information.
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