Talk:Tehachapi Loop

message: How much elevation gain from the bottom of the loop to the top? As far as I can tell, the article doesn't say. - Jmabel | Talk 03:43, 12 October 2009 (UTC)
replies: text: The answer is 77 feet.  I shall add this.--Schwarah191 (talk) 01:57, 8 July 2010 (UTC)
thread_title:  How much elevation gain? 

message: This statement is unsourced, and my understanding is that in fact Amtrak has never, since its founding, run trains over the Tehachapi Loop (other than detours), because the train would take four hours over this route whereas a bus takes less than two to get from LA to Bakersfield. As far as I know, this wouldn't change even if UP lifted its "prohibition" on passenger trains on the loop. 75.83.62.201 (talk) 23:20, 28 January 2012 (UTC)
thread_title:  Does Amtrak's San Joaquin decision really have anything to do with a Union Pacific "prohibition"? 

message: Information I hoped to find in this article was this: what was the geographical challenge that the railroad faced here, & why did they decide that a helix would be the best solution for it? I studied the photo, & there doesn't seem to be any obvious problem--say a steep elevation, or a hill or depression, that required a switchback--that the configuration solves. It almost looks like an engineering feat that was performed because it was cool. (But I suspect there was an understandable reason for laying the track this way.) -- llywrch (talk) 22:23, 19 August 2013 (UTC)
replies: text: Of course there is a "steep elevation": The problem is the height difference between Bakersfield and the summit; this was a good location to lift the line a fair bit to overcome that difference. If you are capable of planning trafficways(like roads and railroad lines), you might take a survey map and a pair of dividers and plan alternative routes - there are certainly quite a few, but you will work for a few days to find some that will make economical sense. (Looking a photographs never helps when planning traffic ways, BTW). --User:Haraldmmueller 17:41, 2 April 2018 (UTC)
replies: text: William Hood first conducted a preliminary survey of the route over Tehachapi Pass while working for the Central Pacific Railroad in 1868. It was on a 2.2% grade, holding to the West side of Tehachapi Creek canyon. So, Hood was already familiar with the area’s topography when in the summer of 1872 he conducted surveys at 1.3% and 2.0 % grades. The difference between the grades is the length of the line, which may also include additional tunnels and bridges, all of which increases the cost of construction: a steeper constructed grade is less expensive. Other alternative location surveys were prepared, including one that had the railroad crossing itself in a loop. The alignment with the loop wasn’t selected until just before construction started on that portion of the line in 1875. The genius of William Hood was his ability to look at the topography in the wide part of Tehachapi Creek canyon and see a way to shorten the length of the line and avoid additional difficult construction, saving substantial cost. The Tehachapi Loop was the first use of a loop by a railroad to gain elevation in the U.S., and probably the world. From Tehachapi by John Signor, 1983. Sixtypoundrail (talk) 23:49, 1 November 2021 (UTC)
thread_title:  Why was this built this way? 

message: I think the headline wording is an exagerration - maybe a huge one even. Compare the given 40 trains a day to some examples from Sweden at http://jvmv2.se/forum/index.php?id=66517:
* Åstorp-Helsingborg 115 trains a day (!)
* Malmbanan, also ca 40 trains a day, > 15 * 10^6 metric tonnes of ore a day between Kiruna and Narvik. 
* Ostkustbanan with two single track sections north of Uppsala, ~50-60 trains a day
* Former single track line Södertälje hamn - Södertälje centrum: 12 trains/hour in peak traffic (now double-tracked). Unsure how many a day in total but obviously many. Used to have most traffic on a single track line in Sweden.
Other examples should hence be quite simple to find...?
37.247.12.251 (talk) 21:13, 8 April 2015 (UTC)
replies: text: Yes - those 40 trains are certainly not that much. The Tauernbahn in Austria had 70 to 80 trains a day when it was still single track 1970s and 1980s). So, this (unsourced) claim should be removed. However, a claim to one of the single-track lines with the highest amount of freight hauled (in tons) would probably be in order (maybe together with lines like the Malmbanan and maybe some other ore transporting lines). --User:Haraldmmueller 17:46, 2 April 2018 (UTC)
replies: text: Agreed. I have removed the unsourced claim. Zazpot (talk) 23:52, 24 October 2018 (UTC)
thread_title:  "Busiest mainline of the world" 

message: AFAIK, there is only one tunnel on the loop ... This should prboably be "The Tehachapi line ..." - but then subsequent sentences are off, as they are talking about the loop. --User:Haraldmmueller 18:41, 24 October 2018 (UTC)
thread_title:  "The Tehachapi Loop took under two years to complete, featuring 18 tunnels, 10 bridges, and numerous water towers for the steam locomotives"