Tightness of turns vs train speed: my standard.

[JonMyrlennBailey]

In American standard gauge, my rule of thumb is for each and every 100 meters of curve radius above zero, I set a maximum allowable speed of 10 MPH.

That is:

100 meter radius = 10 MPH max
200 meter radius = 20 MPH max
250 meter radius = 25 MPH max
500 meter radius = 50 MPH max

and so on.

If the curve varies in radius from one spline point of track to the next, I base the maximum "comfortable" speed allowable on the tightest part of this track section and determine the value of my speed limit signs accordingly. I use the track curve radius tool to determine this. A curve with 175 meters in its tightest spot will limit the train to 15 MPH through here since there are no 17 MPH speed limit signs. 20 MPH through here would be a bit snappy. Trainz speed limit signs are issued in multiples of 5 MPH starting at 10 MPH. I can sense how snappy trains are taking turns at given speeds. Passenger and freight trains are not roller coasters or slot cars so they don't snap around tight turns.

 

[pware]

Using the track Superelevation feature in Trainz will allow you to increase those speeds.

 

[JonMyrlennBailey]

Using the track Superelevation feature in Trainz will allow you to increase those speeds.

I rode the California Zephyr in 1986. The centripetal force was never great enough to overturn a lousy cup of Amtrak coffee in the dining car. If cups and plates and bowls and glasses don't slide across the dining table on the train, then railroad cornering speed and lateral acceleration is probably at an acceptable level. The Amtrak train was no canyon carver for speed in the mountains of Utah and Colorado. There are 10 MPH zones in some parts of my cloned Avery-Drexel and West of Denver routes for sure. American mountain trains are quite slow.

 

[grazlash]

We are lucky here in Australia, where the two most popular states for Trainz routes have ample curve and speeds, gradient and signal diagrams available to the public, including disused lines.

 

[oknotsen]

Curves and railway speed per country:

Minimum railway curve radius - Wikipedia

en.wikipedia.org

 

[JonMyrlennBailey]

Curves and railway speed per country:

Minimum railway curve radius - Wikipedia

en.wikipedia.org

Looking at that chart, some of the curves on West of Denver-Moffat Tunnel (Union Pacific) mainline are as tight as 100 meters right near spline points. This is where my freight and passenger trains creep along at 10 MPH. Most American rail lines were built before 1930. High-speed rail travel has never been a priority in America. I was shocked at how slow the Amtrak train moved through the mountains of Utah and Colorado when I traveled by the California Zephyr to Denver in the summer of 1986. Automobiles on I-70 seen out the train window were passing my train as if it were up on jack stands. In California through the Sierra Nevada, the train could go slow at times. The train would then speed up to Interstate speed going through the flat open deserts of Nevada. For such a streamlined-looking passenger train it can be a real crawler in the twisties. Americans in a big hurry get on a jet plane.

 

[JimDep]

I rode the California Zephyr in 1986. The centripetal force was never great enough to overturn a lousy cup of Amtrak coffee in the dining car. If cups and plates and bowls and glasses don't slide across the dining table on the train, then railroad cornering speed and lateral acceleration is probably at an acceptable level. The Amtrak train was no canyon carver for speed in the mountains of Utah and Colorado. There are 10 MPH zones in some parts of my cloned Avery-Drexel and West of Denver routes for sure. American mountain trains are quite slow.

That has always been the measure of a good engineer. Do the water test and take the turns as fast as possible without spilling to give your passengers a comfortable ride.

 

[JonMyrlennBailey]

That has always been the measure of a good engineer. Do the water test and take the turns as fast as possible without spilling to give your passengers a comfortable ride.

Railroads probably have some other metric to set speeds. But I am certain that if a train hits a turn so hard it upsets tableware, it is unacceptable even for Amwreck, oh pardon me, Amtrak.