Based on my investigation, a higher train braking force is not necessarily better. Based on the scenarios I tested, the general conclusion is this:
- High brake force benefits short train trips. The benefit decreases with longer train trips.
- At a given intersection (simple intersection), if a train has no conflict with any other train OR if a train is going to come to a complete stop regardless of the brake force, go with a high braking force. (This scenario doesn't always happen, keep in mind)
- At a given intersection, if a train will conflict with another train, it is BETTER for the train with the red signal to slow down so that it reaches the signal with some speed remaining, rather than stopping completely.
Details of Test Setup:
One day, I was watching my trains move around my base (as one does), and I started thinking about how trains interact at an intersection. I know in real life, if you come to a stop light, it’s better to time it so that you reach the light with some speed, rather than speeding up and coming to a complete stop at the light. This should be true in factorion, so I wanted to investigate. I used a timer and various scenarios to see the time improvement vs brake force. I used the console to set the brake force between 0 and 2.5. I did look at other bonuses, but there isn’t any change <0. There is a little bit between 2.5 and 3, but not enough to spend the time to worry about it)
I am using a simple roundabout for my base. I know it’s not the best, but it hasn’t hurt me YET. I set up a comparison with various scenarios and used naknak’s really awesome train timer to measure the effect of changing the brake force bonus via the console. (viewtopic.php?t=53911)
I performed 4 scenarios and timing each of them and made a table based on the time. The four scenarios are:
- Measure the time of ONE 1-4 train station to station with a distance of about 600 tiles.
- Measure the time of TWO 1-4 trains station to station with a distance of about 600 tiles.
- Measure the time of TWO 1-4 trains across the roundabout only.
- Measure the time of ONE 1-4 train station to station with a distance of about 8300 tiles.
So, what are the results? Scenario 1, with one train travelling ~600 tiles had the most improvement with higher brake force. So with a brake force bonus set to 2.5 the time was faster than a bonus of 0 by about 14%. HOWEVER, from scenario 4, with one train traveling about 8300 tiles, the improvement was only 2% from a 0 bonus to a 2.5 bonus. This means that higher brake force really only benefits short train trips. Technically, the larger the ratio of brake time to total travel time, the more effective higher brake force is.
When comparing station to station time with TWO 1-4 trains travelling ~600 tiles and meeting at the roundabout at about the same time, the improvement in time isn’t that great. Scenario 2 shows this, with a 2.9% improvement between a bonus of 0 and 2.5. The reason for this small improvement is due to the overall improvement station to station of higher brakes, but the considerable reduction in time to go through the roundabout (Scenario 3). Scenario 3 measures the time change of one train through the roundabout. This train is the one that has to wait at the intersection. What this means is that it is FAR better for a train to approach an intersection slower so that when the track becomes free, the train has not come to a complete stop. With a brake force bonus of 2.5, the train got through the roundabout ~15% slower than with a brake force of 0.
Below is a chart of the percent difference in time vs. a change in brake force. A higher percentage means the time has improved (is faster) compared to the case of brake force bonus = 0. Conclusion
So, the conclusion is that a higher brake bonus is better in some scenarios, but worse in others. It is worse for a train to come to a complete stop at an intersection rather than coming to the intersection with some speed. In my opinion, improving the situation when trains interact at intersections far outweighs the improvements that a higher brake force bonus does provide.
What do we do about it?
For now, don't research higher brake forces. Ideally, if a train is approaching a red signal, the train should slow to a speed that will allow the train to arrive at the braking point of that red signal just when the signal turns green, so that the train is travelling at maximum POSSIBLE speed when it crosses the signal rather than being at a complete stop. I don’t know if a mod can do this, because it could depend on many trains approaching a given intersection. But, that’s how to fully optimize trains when they interfere at an intersection.
It took me a few days to do this to see if brake force research is really better. So I hope it helps someone, I am certainly open to questions.