Earthquakes

[GP-9_Man11786]

How do railroads respond when an earthquake hits their territory? Do they have procedures in place for that type of situation? Also, when tracks cross a fault line, is there any type of special construction required?

[CSSHEGEWISCH]

Based on several relatively minor earthquakes in California in the recent past, railroads will stop everything in the area until the right-of-way can be inspected for possible damage.

[mudchicken]

Absolutely they have procedures. Each railroad does things slightly differently, but the base document in most cases is AREMA Chapter 9. (I worked with two ATSF guys that helped write the initial document) www.arema.org/files/library/1999_Conference_Proceedings/00048.pdf We always hoped for 4.9 on the Richter scale or below, plus having the epicenter over 100 miles away.

[PNWRMNM]

As to special construction crossing a fault line, I worked for SP, but not in engineering, and am 99% confident there was no special construction when crossing a fault line. In part because I do not know of anything that can be done differently, and many faults are not identified now and certainly were not when the lines were built. I do recall one bridge on the Coast Line west of Watsonville that crossed either literally over or very near the San Andreas fault. I remember that it had a device on it to detect misalignment of the bridge. Mac

[blue streak 1]

mudchicken

We always hoped for 4.9 on the Richter scale or below, plus having the epicenter over 100 miles away.

 

But MC isn't some rail line almost always closer than 100 miles except for off shore quakes ? 

 

[mudchicken]

blue streak 1

mudchicken

We always hoped for 4.9 on the Richter scale or below, plus having the epicenter over 100 miles away.

 

But MC isn't some rail line almost always closer than 100 miles except for off shore quakes ? 

 

Yep -Inside the radius of 100 miles, you stop and then take off at restricted speed until 4.9 and below is confirmed and you are given the "all Clear"...over 4.9 and restrictive steps kick-in and some of the radii change. Over 6.0 and you park it. (Be prepared for USGS to waffle on the magnitude for hours)

http://www.arema.org/files/library/1999_Conference_Proceedings/00048.pdf  (server was on the fritz last time, sorry - Link is now active.) This gives you the flavor of the seismic suggested standard set by AREMA. Look inside at about pages 6 & 7.

It's not only bridges that need inspection. Signal systems, especially older ones have issues along with track (esp moving parts of the  switch and spring frogs)....When one of these rascals happen, it's amusing to see how powerless some of the operating supervisors instantly become when they are totally dependent on the track, bridge, signal and engineering troops that are qualified to inspect.

Quite a thrill to see a seismic wave go through an intermodal yard or a tunnel. (done both - or try looking at pin connections on the top chord of a thru-truss when there's an aftershock 3 hours later)

[Paul_D_North_Jr]

GP-9_Man11786

[snipped - PDN] . . . Also, when tracks cross a fault line, is there any type of special construction required?

For the track (only) per se - no, none that I'm aware of; conventional track construction is pretty resilient.

Bridges - absolutely.  There are whole courses and a committee and chapter of the AREMA Manual devoted to that, usually called "Seismic Design for Railway Structures" or similar - see:

https://www.arema.org/committees/cf/c9.cfm 

https://www.arema.org/files/pubs/mre/AREMA_MRE_2013_TOC-Vol2_Ch9.pdf 

Seminar on "Seismic Design of Railroad Bridges" (from https://www.arema.org/Seminars/index.aspx ):

"This seminar will teach the practicing bridge designer how to apply the seismic design procedures of AREMA Chapter 9 to railroad bridges.  The seminar will be conducted by current members of AREMA Committee 9 with practical experience designing railroad bridges in high seismic regions of North America. The seminar will provide the practicing bridge designer with the skills necessary to design typical railroad bridge structures for seismic loads.

Contact Hours: 6"

Usually the first need is for a lot of special and detailed analysis.   Fortunately, most railroad bridges have and will perform well with earthquake loadings, because the bridge already has to be tough enough to stand up under train loadings for many years.  Often the biggest change is to beef-up the supports - piers, abutments, foundations, bearing points, etc.  For the bridge 'superstructure', more or better bracing and attention to connection details are the primary points of concern.  See the following for more info:

"SEISMIC DESIGN OF RAILROAD BRIDGES", a PowerPoint-type presentation by Robert Matthews of DMJM+HARRIS, dated 3/6/2002 (29 slides/ pages, approx. 298 KB electronic file size in this 'PDF" format) at: http://www.structsource.com/pdf/rrintro.pdf  See esp. slides 2, 13, 15, 16 ("For areas with soft soil conditions and high seismicity, or close proximity to known faults, or for special bridge projects, a site-specific hazard analysis is preferred."), and 24 - 29. 

CalTrain's 2003 "STANDARDS FOR DESIGN AND MAINTENANCE OF STRUCTURES, CHAPTER 4: Design Guideline for SEISMIC DESIGN", pages 4 -1 through 4-11 inclusive (79 through 90 of 155) at (155 pages, approx. 7.73 MB electronic file size in this 'PDF" format):

 http://www.caltrain.com/Assets/_Engineering/engineering-standards/PCJPB_Stnd_for_Design_Structures_A_001-155.pdf 

See especially section 4.9 - Seismic Risk on pages 4-10 and 4-11 (1-1/2 pages) for a 'light' technical discussion of this subject. 

Tunnels - I believe that present day designers would avoid that as much as possible.  However, in some cases - such as long-established alignments from 100+ years ago, or where the route just has to go there to provide the desired service (see: "Committee 9 tours the Alaskan Way Viaduct Replacement Project in Seattle, Wash., June 20, 2013" at: http://www.wilsonco.com/sites/default/files/images/Arema.pdf [1 page, approx. 2.27 MB file size in this 'PDF' format) - there may be no choice, and the design has to allow for the motions and forces that may be caused by an expected earthquake, as well as emergency evacuations, responses, etc. 

- Paul North. 

[Paul_D_North_Jr]

mudchicken

[snipped - PDN] . . . http://www.arema.org/files/library/1999_Conference_Proceedings/00048.pdf  (server was on the fritz last time, sorry - Link is now active.) This gives you the flavor of the seismic suggested standard set by AREMA. Look inside at about pages 6 & 7. . . .

The link above provided by my feathered friend is to this paper:

"RAILROAD POST SEISMIC RESPONSE OPERATION AND INSPECTION GUIDELINES", By: William G. Byers, P.E., Burlington Northern and Santa Fe Railway (sic as to the "and" in the BNSF names), 20 pages, approx. 289 KB electronic file size in this 'PDF' format.

- Paul North.