0 Members and 1 Guest are viewing this topic.
No clue. I've often wondered that myself. There was another three headed-dwarf (pictured below) coming off the old siding at Summit Switch, but that one makes some sense because the next signal is the crossovers at Tehachapi so if you were heading out, crossing over to main 2, then being crossed back over to main 1 at Tehachapi, that signal needed the ability to show you a Diverging Approach Diverging (red over yellow over yellow) aspect. That scenario doesn't apply to the signal at the Bealville crossover, so maybe someone else can shed some light.BTW, I got an answer on Trainorders re: the Approach Diverging aspect change and posted it in the thread, but it fell off as the last post on the last page. Just wanna make sure you didn't miss it.
Thanks. About north Walong... So putting this together with your other post, the reason for no yellow was because this was the 'double-blocked' red. When you look at how short the distance is between north walong and 3507, that double blocked red makes some sense. In fact it's remarkable that 3507 is half the distance from Walong than it is from Woodford. And before Woodford was lengthened in 1975, it would have been about 3 times the distance! Which brings me back to another question...Anybody know if there used to be another set of intermediates closer to Woodford? In this photo from before the siding was lengthened there isn't a lower head on 3507 northbound. (Compare to link from post #1.) Perilous as it may be to apply logic to SP signal history, my supposition is that there may have been another set that was the mirror image of these. (Or in other words, like the signals between Rowen and Cliff, or Bealville and Caliente.) When they lengthened Woodford, it would have no longer made sense to have two sets, but the approach signal at 3507 would have needed the lower head added. It would also make sense if they put in the double-block red at north Walong about this time. Too speculative? Anybody ever see another set of signals? (Mike?)
That seems entirely plausible. The absence of a lower head on the 3507 westbound signal in the photo you linked certainly suggests there was another pair of intermediates further down the mountain. The only place I know of on the hill where there was a single head signal protecting the block prior to a 2-headed signal capable of displaying a diverging aspect was on the signal bridge at 326.9 before it was lost to the great flood of 83. A westbound train running on main 1 to be crossed over at Sandcut would have seen a straight approach here.Interestingly enough, even when the new signals were put in place after the flood, the replacement mast signal still featured only a single head. Perhaps westbound movements on main 1 in this area of bi-directional CTC were so infrequent (given that the main obvious purpose of the CTC here was to allow eastbounds to run up main 2 around other eastbound traffic picking up helpers at the now-removed helper pocket) that it wasn't considered cost-effective?
Yes, I do believe that is a dwarf as well. It was replaced with a full searchlight some time around 2005-6:http://www.railpictures.net/viewphoto.php?id=139275&nseq=308http://www.railpictures.net/viewphoto.php?id=239101&nseq=212...
Thanks again for all the info and clarification. Fascinating stuff!Yep, same flood (1983). Here's a shot showing the amount of damage down around Bena. Pretty incredible stuff.http://www.railpictures.net/viewphoto.php?id=55734&nseq=7
... I am guessing/assuming that the marker would have been white but if anyone has any info to the contrary please speak up. ...
Ummmm Ouch!?!?!?!?
The report they filed read like a battlefield casualty list. On the north slope, the narrows of Caliente Creek between the loop at Caliente and Sandcut - historically vulnerable to high water - were particularly hard hit. So swift were the waters that Caliente Creek jumped its banks in the vicinity of the first crossing cutting a new channel through Bena to Walker Basin Creek. At the Walker Basin Creek bridge the west subgrade was washed out for 250 feet taking out the helper spur. The No. 1 (north) track was left swinging in mid-air from the bridge to the road crossing at Bena. Track and fill were completely gone from the east switch at Bena to the first crossing of Caliente Creek and from the first crossing all the way to the west switch at Caliente, ten other major washouts had occurred. Caliente was out of service with all three tracks undermined at the west end by a washout 200 feet long by 15 feet deep. The loop and third crossing bridge at Caliente had suffered at the hands of the flood and the west end of the bridge had sunk two feet and was 1.5 feet out of line. Further up the line, the short siding at Woodford was washed out for 300 feet and a culvert had plugged cascading water and debris over the tracks for a quarter of a mile. The west end of tunnel No. 17 was obscured by a slide 40 feet long and four feet deep. On the south slope Cache Creek overflowed depositing from one to three feet of mud and rocks on the tracks between Cameron Canyon Road and the crossover at Cameron. Further down the hill, in the narrows at mile post 371.4, both mainlines were washed out for 250 feet. On the big curve below Warren a long running side-wash had occurred with the westbound main track being left under¬mined and swinging in mid-air at mile post 375.7. In addition, the Saugus line was out of service with most of the damage confined to the section between Ravenna and Lang. The Palmdale-Colton cutoff was relatively undamaged.
That incredible part to me is that, in spite of this damage report quoted from John Signor's Tehachapi book, trains were again running between Mojave and Bakersfield 9½ days later.
Cool vintage vid:Starting at 15:40, this is looking to me like a red over yellow as the train takes Walong siding, but it is kinda hard to tell in this old footage... what do you folks think?Ed
Nice find Ed. I agree, red over yellow at Walong. Interesting reason that the train was running through on the siding! Also, at Bealville, red over yellow, even though the next signal is yellow. These both confirm what kc9jts has said about the lower heads at sidings having yellow as least restrictive. I gather these signal heads didn't even have green color lenses? Another note: confirmed that the southbound signals at south Bealville were on separate approach lighting relays. Also, maybe the video quality just is not good enough, but I thought it was weird that when the Bealville main signal came on it seemed to be green even though the rear of the helper set was still behind it. Is that possible?I wish they hadn't skipped over so many signals (Sandcut and Tehachapi bridges, for example). But I really like what that gyralight does in the tunnels.
You are correct; the lower head on the facing signal at a control point on Tehachapi (end of siding) had Red/Yellow/Lunar searchlight mechanisms. In the few odd scenarios that they needed a green on a the lower head of a facing signal (such as the signal for the Bealville crossover going southbound) then the lunar was often on a third signal head.
It is "possible" that there could be a green on a signal that governs occupied track; but that means somebody screwed up wiring or some mice got into a case or something Under normal circumstances it would not be likely or possible. I am thinking that the signal is red but it is hard to tell due to video quality. I do like the gyralight in the tunnels as well. As info there are some parts of the SP that were ABS (not CTC) that would allow an opposing signal to clear right behind a train once it was clear of the governing track circuit; much of the Phoenix sub functions this way but not on Tehachapi.
Interesting. What would the lunar be for? Did they allow following moves onto sidings?I understand now. I was thinking that the Bealville signal would change to clear once the helper set was fully north of the signal, as it would on ABS track, forgetting that this wouldn't be the case with CTC. (Coast line was also mostly ABS, right?) I agree that the video quality is too poor to judge color, and it's almost certainly just red for the whole clip.
Author
Topic: Tehachapi signalling thread - prototype (Read 72897 times)
