It is imperative that breakdowns are kept to an absolute minimum to ensure that your trains continue to roll - the goal is to have a rail network that is so efficient, there are no breakdowns at all! Keeping your trains running at optimum reliability might seem as simple as changing it's servicing schedule from 150 days (the default) to 100 days or less. But there is far more to it than that...

    The first and most obvious (and annoying!) problem with this is that you have to re-set the schedule of every train you purchase, even if it is to replace an existing train. The service schedule is not retained (unlike the orders).

    The second problem is that trains making the most profitable runs are usually running on very long routes. One such train might leave the station just as it is due for a service. The computer determines which depot is nearest (in distance - direction of travel is not considered) to that train and instructs the train to go to THAT depot.

    Unfortunately, the computer can't (or won't) determine if that is the depot to which the train can arrive the quickest, and it won't tell the train to: one, stop at any other depots it comes across, and two, reverse direction to find that nearest depot. (But with "one-way" signals in place along dual tracks, the train can't reverse direction and travel any great distance anyway.) Instead, the train stubbornly ploughs onwards, relentlessly looking for a way to turn around. Often, the only place to turn around is the destination station. The train gets there, ignoring depots near the station, and turns back to the original depot. Very frustrating!

    The end result is that by the time the train gets serviced and returns to the destination station to finally unload it's cargo, it has travelled more than twice the required distance, and your profits from that run reflect this in a bad way. And I mean bad as in BAD.

    The solution to this vexing dilema is to be in control of when and where the trains get serviced without leaving it up to chance. ie To able to 'force' the trains into depots

    This design does come to mind as a solution to the problem, however, it only works in cetrain situations. Because the section of track that by-passes the depot is missing, some circumstances lead the games' route calculations to ignore the route alogether and so trains may be unable to find a route to their destination. I don't recommend using this design - it's better to invest in a couple of extra peices track and know that the trains can successfully find their way.

    Examine the following screenshot - with your knowledge of how the signals operate you should be able to see how this "mandatory service depot" or "force depot" works. (This solution depends on the signalling features introduced in Transport Tycoon Deluxe. Transport Tycoon Original does not have the advanced signalling required to make this work.)

    All trains running on the track come upon a fork in the tracks. By continuing straight, the train would meet the 'wrong' side of a "one-way" signal. It sees this and makes the turn into the depot, where it's reliability rating is increased to maximum. It then leaves the depot and continues on.

    Here is an alternate arrangement of the same thing that is more space efficient - it occupies the same number of squares, but is not as wide. A very useful application of this arrangement is in implimenting a "dual depot" (or more if you want) that gets trains in and out alot quicker than one depot on it's own. Observe:

    You can see that a train reaching the fork will see the "two-way" signals in front of it and choose the track that is free. This allows a train to enter one depot while another train is either leaving the other depot, or still going into it.