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Measures to Reduce Service Disruptions when Restrictions are in Force due to Strong Winds

East Japan Railway Company

November 7, 2006

In light of the derailment that occurred on the Uetsu Line on December 25, 2005 between Sagoshi and Kita-Amarume, train speed limits based on wind speed were revised* on January 19, 2006 on all sections where such restrictions apply. Speed limits due to strong winds have been put in place more frequently as a result, causing significant inconvenience to passengers.

JR East has decided to implement the following proven measures on lines chiefly in the Tokyo metropolitan area to reduce the effect of restrictions during strong winds on service.

  • Windbreak fences
    To be installed on nine sections of track on four lines in the Tokyo metropolitan area
  • Strong wind warning system
    To be installed on twelve sections of track on three lines chiefly in the Tokyo metropolitan area

Windbreak fences are due to be installed in fiscal 2006 and 2007 (some will be ready for use by the end of fiscal 2006), while the strong wind warning system is due to be installed in fiscal 2006.

It is expected that windbreak fences will reduce the frequency of service restrictions and that the strong wind warning system will shorten the time for which such restrictions are in force.

Under the revised restrictions, at a wind speed of 20 m/s, train speed is limited to 25 km/h and at a wind speed of 25 m/s, service is suspended.

1. Windbreak fences

(1) 

Overview of windbreak fences

 

Windbreak fences are installed to reduce the force of the wind acting on the train. Standing approximately 2 meters tall (standard rail level), fences are constructed using bent back steel plates with perforations.

Overview of windbreak fences Overview of windbreak fences

Example of a windbreak fence (on the Kawagoe Line between Sashiogi and Minami-Furuya)

(2) 

Lines and sections on which fences will be installed

 
  Line Section Location of windbreak fence(s) Target completion date
1 Musashino Line Misato–Minami-Nagareyama South side Fiscal 2007 (by the end of fiscal 2006 for some sections)
2 Tohoku Line Kurihashi–Koga Both sides
3 Joban Line Fujishiro–Sanuki Both sides
4 Keiyo Line Shiomi–Shin-Kiba South side
5 Shin-Kiba–Kasairinkaikoen
6 Kasairinkaikoen–Maihama
7 Ichikawashiohama–Futamatashimmachi
8 Futamatashimmachi–Minami-Funabashi
9 Kaihimmakuhari–Kemigawahama
For reference Tokaido Line Nebukawa Station Both sides  In use (completed in July 1991)
Joban Line Yonomori–Ono West side  In use (completed in February 1996)
Kawagoe Line Sashiogi–Minami-Furuya North side  In use (completed in April 1998)
Uetsu Line Sagoshi–Kita-Amarume West side  Scheduled to be completed by the end of November 2006
Tohoku Line Fujita–Kaida West side  Scheduled to be completed by the end of November 2006
Lines and sections on which fences will be installed
(3) 

Restrictions in areas with windbreak fences installed

 
Restrictions in areas with windbreak fences installed

2. Strong wind warning system

(1) 

Overview of the strong wind warning system

 

The strong wind warning system uses continuous wind speed measurement data to forecast the maximum possible wind speed when the train passes through designated sections of track that are subject to speed restrictions during strong winds (hereinafter referred to as maximum forecast wind speed). Restrictions are put in place when either the maximum forecast wind speed or measured value (actual wind speed) exceeds the regulation value. On the other hand, restrictions are lifted when both the maximum forecast wind speed and actual wind speed both fall below the regulation value.

Installation of the strong wind warning system brings the following benefits.

  • Under the current system, restrictions are put in place when the actual wind speed exceeds the regulation value. Installation of the strong wind warning system means restrictions can be enforced also when the maximum forecast wind speed exceeds the regulation value, which provides added safety compared with solely basing decisions on the actual wind speed as is done now.
  • Under the current system, after the actual wind speed exceeds the regulation value even momentarily, restrictions remain in force for 30 minutes after the wind speed drops below this level irrespective of wind conditions during that time. With the strong wind warning system, restrictions can be lifted as soon as both the actual wind speed and maximum forecast wind speed both drop below the regulation value, which reduces the time train speed regulations are in place or service is suspended by an average of 20 to 30%.

Example of restrictions on a section of track fitted with the high wind warning system

Example of restrictions on a section of track fitted with the high wind warning system
Example—bridge over Arakawa River discharge channel between Shin-Kiba and Kasairinkaikoen on the Keiyo Line (October 1, 2002)
(2) 

Lines and sections on which the system will be installed

 
  Line Section Section
1 Musashino Line Misato–Minami-Nagareyama Fiscal 2006
2 Koshigaya Terminal–Yoshikawa
3 Kita-Asaka–Nishi-Urawa
4 Tohoku Line Kurihashi–Koga
5 Fujita–Kaida
6 Kosugo–Shiroishi
7 Iwanuma–Natori
8 Higashi-Sendai–Iwakiri
9 Matsuyama-Machi–Kogota
10 Joban Line Fujishiro–Sanuki
11 Hirono–Kido
12 Soma–Komagamine
For reference   Keiyo Line Shiomi–Shin-Kiba  Installation completed on August 11, 2005
Shin-Kiba–Kasairinkaikoen
Kasairinkaikoen–Maihama
Ichikawashiohama–Futamatashimmachi
Futamatashimmachi–Minami-Funabashi
Kaihimmakuhari–Kemigawahama
Lines and sections on which the system will be installed
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