Why is the passenger train speed on the BNSF racetrack in Chicago only 70 not 80? This is just from my observations from riding trains on that... they never seem to go over 70.
The 70 MPH speed limit may be for safety reasons. There are still numerous grade crossings from Berwyn heading west and many of the suburbs are developed right up to the edge of the right-of-way, with streets often paralleling both sides of the right-of-way. Also, many stations are only about one mile apart.
It's cab signalled, so it could be even higher than 80. I'll pile on and agree that the practical, time savings from running a bit faster just aren't worth the effort. I'd guess the signals were laid out for 70 mph long ago and increasing speed either means respacing them or a fancier braking system on the passenger trains.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Would not a level of fuel economy, also be a factor?
I think it has been reported around these Threads that fuel economy goes down as speed increases?
oltmannd It's cab signalled, so it could be even higher than 80. I'll pile on and agree that the practical, time savings from running a bit faster just aren't worth the effort. I'd guess the signals were laid out for 70 mph long ago and increasing speed either means respacing them or a fancier braking system on the passenger trains.
What about AMTAK which only stops at Naperville? + many Metra operate express skipping many stations.
As No. 39 was approaching Naperville, the speed was about 80 miles per hour.
http://ntl1.specialcollection.net/scripts/ws.dll?file&fn=6&name=S%3A%5CDOT_56GB%5CRailroad%5CWEBSEARCH%5C2988.PDF
It looks like speeds of 80 were achieved in the past.
A top speed of 80 would save a minute of schedule time over 70 m.p.h. only if it could be sustained for about six miles. I suspect an express train from Naperville might save two or three minutes, tops, on a trip into Chicago. UP West would fare no better on a trip in from Wheaton. On the UP, you'd still have those 50-mph curves between College Avenue and Glen Ellyn, and need to slow down to 40 for that crossover in Elmhurst, right smack in the middle of the run, and restoring the speed back up to 80 would take a lot of fuel (some of that could be saved by express runs using the 50-mph crossover in Lombard instead).
Speaking of such things: I haven't been over on the BNSF line for a few years now, but unless they've really done some work there, the ride at 80 would be uncomfortable, to put it mildly.
Carl
Railroader Emeritus (practiced railroading for 46 years--and in 2010 I finally got it right!)
CAACSCOCOM--I don't want to behave improperly, so I just won't behave at all. (SM)
Yeah the track is nice and smooth on the racetrack. For most Metra trains, they stop too often to do 80 but the express metra or Amtrak could definitely accelerate to 80.
I've heard rumors of Metra engineers who were behind their schedule by a few minuts "cheating" the speed limit and really putting the "pedal to the metal" to make up a few minutes. If true, this may be stimulated by a "pay for performance" deal with crew, is such a thing exists...who knows.
I'm guessing the signals allow 75 at least-- as I recall that limit lasted into the 1970s. In the 1940s the limit was probably 80 for the Exposition Flyer and 90 for Zephyrs (beyond Downers Grove, anyway).
Edit: In 1943 timetable speed on tracks 1-2 was 80 La Vergne to Downers Grove; lightweight trains were allowed 95 west of Downers Grove. Track 3 was 70 mph.
In 1950 speed was nowhere more than 75-- the CTC is newer than that, isn't it? So maybe the signals spacing is set for 75.
The district has been boarded 79P/60F for years wth restrictions inside the limits (BNSF Chicago Sub LS71). The district has too many switches per mile to sanely go faster (you're beating the frogs to death and as Carl points out, there is no advantage to going faster, all you do is eat fuel and brake shoes.) Plus there are gobs of 70MPH and 55 MPH curves in there (Been that way for years) keeping the speed down. 70MPH is a fairly happy medium. Jacking up the speed creates headaches maintaining crosslevel in a curve - Lose a half inch in a small dip and slow order the whole curve 5-10 MPH.... AIN'T WORTH IT.
Amusing to hear some of the non railroader's speed comments....(80 MPH - Where's the ATS inductors?, that additional 1 MPH kicks in all kinds of mandated expen$ive additional standards and precautions...Want 80 MPH+ ? Sure, build BNSF a new freight corridor so all those 25-45MPH trains don't destroy the curve low rail and the turnouts and you don't have welders camped out in there begging a knucklehead overextended DS for track and time to preserve that Class 4 track. 79P/60F). Wanna jack up the fares to cover the extra costs? (thought so)
mudchicken(80 MPH - Where's the ATS inductors?
The ride on the BNSF is pretty rough still doing 70 thanks to the numerous crossovers, and those bridges between Western Avenue and Cicero are pretty rough rides too. Many of the older signal bridges were originally built to handle trains at over 100. Of course BNSF has been replacing a few of these signal bridges per year, and in the CB&Q and BN days, many of the original CB&Q bridges were moved around and modified as the then-new crossovers were installed at the East Lisle, East Naperville and West Naperville.
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