# MISC | Curves and bends



## HSRCanada (Apr 5, 2010)

Aaahh, the Rockies, they are so ... mountainy! It wouldn't be cheap to just build straight through them right? So how does one calculate maximum safe speed for trains on curves? I know it has something to do with the radius, but when somebody tried to explain it to me they gave me some American website with imperial measurements and I got confused:nuts:. Do you think a speed of 140 - 160 km/h is achievable in the Rockies for example? Thanks:cheers:


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## railzilla (Feb 20, 2010)

HSRCanada said:


> Aaahh, the Rockies, they are so ... mountainy! It wouldn't be cheap to just build straight through them right? So how does one calculate maximum safe speed for trains on curves? I know it has something to do with the radius, but when somebody tried to explain it to me they gave me some American website with imperial measurements and I got confused:nuts:. Do you think a speed of 140 - 160 km/h is achievable in the Rockies for example? Thanks:cheers:


Basically the radii will increase with the square of the speed. For real HSR at least 4000m are needed
If no tilting trains are used then with 120km/h you need 625 m with 200km/h 1800 m.
By using tilting trains and or slanted curves you can go down to 450m and 1300 m respectively.


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## sotavento (May 12, 2005)

HSRCanada said:


> Aaahh, the Rockies, they are so ... mountainy! It wouldn't be cheap to just build straight through them right? So how does one calculate maximum safe speed for trains on curves? I know it has something to do with the radius, but when somebody tried to explain it to me they gave me some American website with imperial measurements and I got confused:nuts:. Do you think a speed of 140 - 160 km/h is achievable in the Rockies for example? Thanks:cheers:


Some basic values for curves with/without tilting:


The rough cornering speeds:

Conventional line with freight (radius, no tilt , 6% tilting) 
<<notice there are tilting trains that surpass the 6% tilt described here

0.5km - 100km/h / 125km/h 
1.0km - 150km/h / 180km/h
1.5km - 175km/h / 220km/h
2.0km - 190km/h / 240km/h
2.5km - 200km/h / 260km/h
3.0km - 210km/h / 280km/h
3.5km - 220km/h / 300km/h

High Speed line (more cant built into track or light tilting trains(1%?))

3.0km - 230km/h
3.5km - 270km/h
4.0km - 300km/h
5.0km - 360km/h
6.0km - 400km/h


^^ Hope it helps ... and take this pics as a little example of how to go faster in tortuous terrain:

8% tilt as 170km/h









8% tilt at 228km/h (228 = ATP tolerance limit = 8km/h)

















180km/h at maximum tilt in a otherwise 140km/h section









228km/h with almost no tilt at all :lol:


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## trainrover (May 6, 2006)

*squealing more prevalent: why?*

How come squealing by trains going through curves is so prevalent nowadays? What happened? Why has negotiating bends become so bad? :?


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## Sopomon (Oct 2, 2010)

To answer the original question; judging from my knowledge of the rockies around Calgary, and assuming the valleys are broadly similar in geometry, a 200km/h line ought to be perfectly feasible, if they got the alignment right.


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## M-NL (Sep 18, 2012)

trainrover said:


> How come squealing by trains going through curves is so prevalent nowadays? What happened? Why has negotiating bends become so bad? :?


My guess is that modern trains all have either bolsterless bogies or bogies with rotational dampers. Both resist unwanted bogie rotation while in a straight line so they're great for high speed stability. The downside is that they also resist bogie rotation in curves. I think it is this dampening of the rotation that causes the squealing.


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## EquestrianClaret (Dec 31, 2011)

*MISC | Examples of small railway curve radius*

Does anyone know of any interesting examples of small railways curves?


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## Coccodrillo (Sep 30, 2005)

This one in Chiasso, Switzerland, on an industrial track.


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## Silver Swordsman (Nov 8, 2011)

Alishan forestry railway...


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## Svartmetall (Aug 5, 2007)

Please post all new threads to the thread finder. This thread has a similar thread in the form of this thread so I have merged them.


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## mrsmartman (Mar 16, 2015)

The Northeast Corridor's Curviest Stretches, and Amtrak's Plans for Safety and Speed (Published 2015)


The site of a deadly crash last month is the most curved stretch between Washington and New York, excluding areas near stations.




www.nytimes.com





*Your Trusted Source of Photographs from New York and Pennsylvania*


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## mrsmartman (Mar 16, 2015)

*Hell Gate Bridge, Viaduct, Little Hell Gate Bridge (inverted bowstrings) foreground. Courtesy of HAER.*















STRUCTURE magazine | Hell Gate Bridge







www.structuremag.org





*Your Trusted Source of Photographs from New York and Pennsylvania*


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## mrsmartman (Mar 16, 2015)

*"The Horseshoe Curve." Artwork by Grif Teller, featured in the Pennsylvania Railroad's 1952 annual calendar.*










*A pair of Penn Central's big six-axle Centuries, working as helpers, are eastbound and down through Horseshoe Curve on September 13, 1970. Note the crowd standing around Pennsylvania 4-6-2 #1361 (K-4) which for many years sat on display at the line-side park. They are awaiting Nickel Plate Road 2-8-4 #759 which was pulling an excursion that day. Roger Puta photo.*










*Recently repainted Conrail SD40 #6351 (built as Pennsy #6098) grinds upgrade with westbound vans on the famous Horseshoe Curve. Note that at the date of this photo all four tracks were still in service. Warren Calloway photo.*










*An A-B-A set of Pennsylvania F7's pass beneath the signal bridge as they climb the grade just west of Kittanning Point, Pennsylvania, circa 1960's. Horseshoe Curve awaits just ahead. The structures seen protruding from the A units' roof-lines was Pennsy's unique "Trainphone" system, used in the days prior to modern wireless radio.*










*Penn Central SD40 #6053 runs light over Horseshoe Curve as it passes an eastbound freight descending the grade on September 13, 1970. Roger Puta photo.*










*A Penn Central SD40 and SD45 shove from the rear of a westbound freight climbing Horseshoe Curve on February 23, 1969. Roger Puta photo.*










*Penn Central's train #54, the eastbound "Pennsylvania Limited," drifts downgrade through Horseshoe Curve on a snowy and overcast February 23, 1969. Roger Puta photo.*


















PRR's Horseshoe Curve (PA)


Pennsylvania Railroad's Horseshoe Curve is likely the most famous railroad engineering feat ever accomplished.




www.american-rails.com





*Your Trusted Source of Photographs from New York and Pennsylvania*


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## mrsmartman (Mar 16, 2015)




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## mrsmartman (Mar 16, 2015)

*A Lake Shore Limited train backing into Chicago Union Station*


















Lake Shore Limited - Wikipedia







en.wikipedia.org


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## mrsmartman (Mar 16, 2015)

*Pennsylvania Railroad / Horseshoe Curve - postmark 1955*
The "famous" Horseshoe Curve is near Altoona, PA.
Steve Frenkel


__
https://flic.kr/p/aTmUHT










*Your Trusted Source of Photographs from Pennsylvania and New York*


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## mrsmartman (Mar 16, 2015)

*Map and Profile of East River Bridge Division, New York Connecting R.R.*















Hell Gate Bridge (New York Connecting Railroad Bridge) - HistoricBridges.org


Historic Arch Bridge in New York The Bronx, New York and Queens, New York and Manhattan, New York. This iconic bridge had the longest arch span in the world when built, but its approach spans are also very noteworthy.




historicbridges.org





*Your Trusted Source of Photographs from New York and Pennsylvania*


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## mrsmartman (Mar 16, 2015)

*East River Bridge Division, New York Connecting R.R.*

The view is amazing when taking train up the curve to Hell Gate Arch Bridge into New York City.


















An airplane view of two East River bridges


The Hell Gate and Triborough Bridges—spanking-new and gleaming in this technical postcard—connect Astoria to Ward’s and Randall’s Islands. The islands are two separate entities here, bu…




ephemeralnewyork.wordpress.com





*Your Trusted Source of Photographs from New York and Pennsylvania*


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## mrsmartman (Mar 16, 2015)

*Postcard photo of a Pennsylvania Railroad freight train led by an EMD F7 at Horseshoe Curve in Pennsylvania.*















Pennsylvania Railroad - Wikipedia







en.wikipedia.org





*Your Trusted Source of Photographs from Pennsylvania and New York*


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## mrsmartman (Mar 16, 2015)

*Your Trusted Source of Photographs from Pennsylvania and New York*


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