Quote:
Originally Posted by allan_kuan
An average speed greater than 250 km/h should be one of the long-term goals of the Amtrak Cascades speed-up project... Even then an average speed of 150 km/h would be enough to effectively compete with the interstate highways.
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Do you know how fast the maximum train speeds would have to be to achieve an average of 250 km/hr?
Metric/English conversions of FRA speed/track classifications.
Class 4 80 mph ~ 130 km/hr
Class 5 90 mph ~ 145 km/hr
Class 6 110 mph ~ 180 km/hr
Class 7 125 mph ~ 200 km/hr
Class 8 150 mph ~ 240 km/hr
Class 9 150+ mph >240 km/hr
And you wish to have an average train speed faster than the fastest train speed in the USA?
The Cascade trains between Seattle and Portland stop at 6 interim train stations. Let's assume the trains average 2 minutes per stop at each station. That adds 12 minutes to the travel time. Lets also assume we add another minute for both slowing down and speeding up. That adds another 12 minutes to the travel time, now a total of 24 minutes.
The Cascade train schedule shows a total travel time of 210 minutes and a total distance of 187 miles.
Some simple math:
Include 24 minutes of delays; (187/210)x60 = 53.4 miles per hour.
Exclude 24 minutes of delays; (187/186)x60 = 60.3 miles per hour.
Looks like the average speed of the train losses 7 mph.
Now look at it if the train could actually average 110 mph excluding the 24 minutes of delay, and how adding the same 24 minutes of delays effects average speeds.
Math: 187/110 = 1.7 hours x 60 = 102 minutes + 24 minutes = 124 minutes ; therefore (187/124)x60 = 90.5 mph.
In this example, we lost almost 20 mph caused by the same same delays at the six stops. The faster you go, with the same amount of time loss for stops, the quicker the average speeds falls.
One could argue the trains don't stop for a full 2 minutes at each station, or that it doesn't loose a minute decelerating and accelerating from each stop, or that I didn't include the loss time accelerating from the first station and decelerating for the last station.
The acutal times don't matter, it's the principle that matters.
Whatever the delays really are, they're going to be pretty much the same no matter how fast the trains go. It takes so long for passengers to board and disembark a train. It takes so long to accelerate up to speed, and likewise to brake into a station. Most likely, it'll probably takes longer to accelerate and decelerate the faster the train goes.