For specific SWITCH conditions at or approaching interlockings (Control Points). No such signals were used to control speeds on curves. On CPL’s, the color identified the condition of the block ahead - the markers were additional information.
charlie hebdo ,Euclid ,Overmod, BaltACD, you have all submitted insightful, sage, valid and informative information/observations but what is glaring to me is the significant speed reduction from 79mph to 30mph curve which if and was miscalculated could/did result in disaster. That in the relatively small portion of ‘new’ territory should have been foremost in the engineer’s mind. The reason for it not being, in my opinion is, surprise!, poor vetting, poor training and poor supervision.
Those speed indications sometimes were due to insufficient braking distances at the next signal if a train approached it at full track speed. It is a problem if the next signal is an approach and the following stop signal is one mile away, if traveling at track speed means the train will take 1.1 miles to stop. Having speed signals allows the train to maintain full speed longer since it only has to slow down as it nears the approach signal.
As to speed indications at control points, various routes may use different sizes of turnouts. Without speed indications, trains would be limited to the speed of the most restrictive turnout within the interlocking, even if it was not part of its route that day. Even on a simple single track line with passing sidings it is useful, since not all the power turnouts may have the same turnout number and the alternative is numerous notes in the ETT giving the speed at each; all too easy to miss one.
But I think you knew that already.[:D]
I have seen signals used for speed control on curves but that was quite a different method, on the Toronto subway. It did not use special indications. Instead there was a timing circuit in the occupied block before the signal (and trip arm) at the end would clear. The operators became good at passing the red signal moments after it cleared. There was a lunar below the red that presumably indicated it was controlling speed and the next block was in fact clear. Did Saluda have something similar?
Back in the days when trains would ‘ride the yellows’ - expecting them to go green just before they passed them at track speed … sometimes there were serious consequences when they rode the red in a similar manner - only to find the lead train stopped just past the red.
Unfortunately “riding the yellows” still happens, on CN I know of at least two stop signal violations this past fall alone that resulted from the practice. On Edmonton’s east side in 2011 there was a rear end collision in just such the manner you have described:
http://tsb.gc.ca/eng/rapports-reports/rail/2011/r11e0063/r11e0063.asp
Unfortunately there are many more.
The Toronto subway motormen’s practice CX500 described resulted in a fatal crash in 1995:
https://en.wikipedia.org/wiki/1995_Russell_Hill_subway_accident
I know of a couple locations with short blocks where the preceding signal will display “Clear to Medium*” or “Clear to Limited*” if the second signal is set at stop. Officially that is an improper progression of signals as those locations have no Medium or Limited speed turnouts, but I understand the rationale.
*The signal names changed in the CROR a number of years ago, well before I hired on. For example what was once called “Approach” is now called “Clear to Stop” and “Approach Medium” became “Clear to Medium”. Only the names changed, the indications and meanings did not.
My guess is that that curve will be lit up like my neighbor’s house when they decide to resume service.
I recall some reporting on the reason why the curve was deemed to be necessary. It sounded like straightening the curve was simply not possible, or maybe it is less possible to do after the highway had been built. As I recall, straightening the curve now would require that the track would have to first curve way out to the right, and then start a final curve to the left in order to cross the highway. This would require buying a lot of land to the right side as the 501 approached the curve. If they just started the curve earlier to reduce the curvature rate, then it results in a longer bridge to get over the highway. The curve was also deemed to not be an issue when only running freight trains prior to the introduction of the new fast passenger trains.
I also recall in an interview with the engineer that he indicated that he and all of the other engineers were very much aware of the curve as almost an infamous and dreaded feature of the route. Maybe this strong familiarity with the existance of the curve caused the engineer to let is guard down and underestimate how hard it might be to find it when running.
Now that PTC has been reported as having been installed on the segment of track - are Amtrak-WSDOT conducting non-revenue training trips over the line?
There would be another way to just eliminate the curve totally. That would to build almost perpendicular horizontal supports across the I-5 and build the track across the highway at an acute angle. Note the LAX metro did that as we saw a pictue posted by KP Harrier over a highway . elevation at that location would not be a problem just a matter of $$$
Would save a couple minutes as well !
If the proposed HSR line is ever built PDX- SEA along this alignment that option will be necessary to maintain high speed
I believe that there was a earlier article that referenced a plan to continue the tracks down the north side of I5 and intersect the tracks there, but it required a lot of fill and land.
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charlie hebdo ,Euclid ,Overmod, BaltACD, you have all submitted insightful, sage, valid and informative information/observations but what is glaring to me is the significant speed reduction from 79mph to 30mph curve which if and was miscalculated could/did result in disaster. That in the relatively small portion of ‘new’ territory should have been foremost in the engineer’s mind. The reason for it not being, in my opinion is, surprise!, poor vetting, poor training and poor supervision.
I recall some reporting on the reason why the curve was deemed to be necessary. It sounded like straightening the curve was simply not possible, or maybe it is less possible to do after the highway had been built. As I recall, straightening the curve now would require that the track would have to first curve way out to the right, and then start a final curve to the left in order to cross the highway. This would require buying a lot of land to the right side as the 501 approached the curve. If they just started the curve earlier to reduce the curvature rate, then it results in a longer bridge to get over the highway. The curve was also deemed to not be an issue when only running freight trains prior to the introduction of the new fast passenger trains.
I also recall in an interview with the engineer that he indicated that he and all of the other engineers were very much aware of the curve as almost an infamous and dreaded feature of the route. Maybe this strong familiarity with the existance of the curve caused the engineer to let is guard down and underestimate how hard it might be to find it when running.
When one loses situational awareness the normal reaction is to slow down is it not? He did not.
Who pronounced this person qualified? Someone who is minimally qualified themselves.
As I have said repeatedly the root cause(s) for this tragedy are poor vetting, poor training and poor supervision. Amtrak should be held accountable.
Yes, I agree that the root cause was hiring this engineer. The engineer exhibited very poor judgement in choosing such a flimsy method of knowing when to brake for the curve when so much was at stake. He lacked the common sense to see that. Obviously Amtrak never vetted him for his poor sense of judgment, and lack of common sense. The engineer should have chosen a different line of work.
Actually, I would say that when one realizes he has lost situational awareness…
A properly supervised ,vetted and trained engineer will know where he is at all times. When this engineer realized he was ‘lost’ he still took no action to slow down. That is criminal. It is also criminal in the way Amtrak supervised, vetted and trained him (and others).
Yes, he had to know he was lost. He started out lost with the intenion of finding where he was by watching for key wayside marker points. This process would cast doubt in most peoples’ minds. When you watch for markers to confirm your location, you might lose confidence by thinking you might have missed one. That is the problem when you might find key markers such as mileposts, but do not really know the territory, which is 100% familiarity with every square foot of it. I would not be surprised if this engineer was feeling doubt over the question of whether he had accidentally passed a key marker without seeing it. If he was feeling doubt, he should have slowed down. He must have felt the push of the Amtrak institution relying on him to make the schedule.
Precisely!
Amtrak Operations are in dire need of oversight by a team of experienced
Does anyone know approximately when the NTSB report will be released?