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| (1276188) | |
PHOTOS: SHOO FLY TWO |
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Posted by Jersey Mike on Wed Feb 19 00:38:55 2014 The Port Road Shoo Flys were once considered the holy grail of railfan locations in the Eastern Pennsylvania area. These three structures were built by the pennsylvania Railroad as part of the 1915 Atglen and Susquehanna "Low Grade" project that bypassed heavy grades on the PRR Main Line between Parkesburg and Harrisburg by cutting across hill and dale to join the Columbia and Port Deposit alignment just south of Columbia, PA. When trying to fit in the A&S next to the C&PD between the cliffs and the river the PRR ran into some issues with three local streams that would risk washing out Port Road if they were left to drain under both rights of way. The solution was an innovative "Shoo Fly" structure (I guess they are more aptly referred to as aqueducts) that carried the streams over the Port Road after passing under the A&S. From north to south they were Mann's Run, Fisherman's Run and Fry's Run.Now I said these were considered holy grails because even though the A&S was abandoned in the 1980's and only continued to serve as a 25Hz power RoW for Amtrak, the locations are completely inaccessible due to local topology. To visit all three of the Shoo Flies would require a 7 mile round trip hike from the Safe Harbor Dam to the south or a 9 mile hike in from Blue Rock from the north. In 2007 I used a rather daring shortcut across an active landfill to visit the Mann's Run Shoo Fly, but it was a rather high risk enterprise just to see a bit of historical engineering. Well fast forward some years and it appears that the State of Pennsylvania has completely robbed the railfan community of one of its more cathartic experiences (as well as destroying a vital rail corridor) by turning the former A&S into the Enola Low Grade Trail. It now takes a sum total of 20 minutes to reach all three Shoo Flies via a bicycle on the immaculately manicured roadbed. Of course that was lost in the journey was partly made up by increased access to a large number of PRR era railroad appliances that were just left in place by Conrail when they ripped up the track. In today's segment I will explore each of the Shoo Flies and then double back to show off some of the other historic elements featured along the trail. You can find the full set of photos here. We begin with something completely different. Here is East Penn railway GP9 #1701 sitting near York, PA near US 30.  Heading to the rail trail parking lot we pass through Comulbia, PA with the 1930's vintage COLA tower, which still held the local relay interlocking logic until just a few years ago.  The whole area from Holtwood to Shocks was resignaled by NS to get rid of the Rule 251 operation and US&S 504 code line. Fortunately the catenary structure in this area ws saved from scrapping because it is still used to carry a 25Hz 138Kv power circuit from Safe Harbor to Royalton.  First up is the Mann's Run Shoo Fly. This is the largest of the three streams with a wide trough and high walls.  This one also has the best waterfall effect.  If photos aren't enough here is a video tour of the Mann's Run Shoo Fly. Fisherman's Run is the smallest Shoo Fly with a very narrow trough. It is also having problems with exposed rebar.  Here is the transition for Fisherman's Run from forest stream to railroad aqueduct.  And of course a video tour. Finally we come to Fly's Run which is the widest of the three, but has rather short walls.  This allows for photos of actual trains on the Port Road below...if said trains ran in daylight on this line, which they don't due to Amtrak's restrictions.  View of the pond above the Safe Harbor Dam.  Fly's Run has a little waterfall effect going on as well.  And of course the video tour. The end of the train is at the famous Safe Harbor Viaduct. Technically the trail continues on the other side all the way to Atglen, but because of health and safety the bridge is barricaded off until the money turns up to fix it.  There was a small concrete PRR watchman's shanty on hand with the obligatory keystone.  Unlike the Conewingo Dam, Safe Harbor still uses its original 1930's gantry cranes.  Does anybody know what these hoop things are on the 138kV insulators?  Another plus was that all of the old position light signal mounts were left intact on the catenary poles. The equipment for the 6600 volt 100Hz power supply and the relay cabinets were also in place. The signal power line was used by the Port Road until about 2009 with one of the generating stations being located at the Amtrak Safe Harbor Substation.  At Milepost 28 one of several slide fences had a sort of Spanish moss look going for it.  Wooden pole PRR slide fence construction. This stuff was way over engineered compared to other railroads, especially those out west.  Closeup of the insulator strings on the out of service 25hz 138kV circuit. Each wire carried + or - 64vK as part of a single phase power system.  This trail is a boon for rock climbers and many of the sheer rock faces had already been outfitted with rope anchor points.  From the trail side the original PRR railings were supplemented with something a bit more child proof such as this example at Fry's Run.  The PRR did use steel I-beam poles for its slide fences as well.  Old and new relay huts at CP-CRESS. The 1937 COLA CTC project was in service for over 70 years before being replaced by modern equipment that will be lucky to last 20.  This is former Conrail class Ne 6 caboose #23832 on static display adjacent to CP-CRESS and painted in PRR colors.  I will leave you all with this PRR catenary gantry equipped with sectionalizing switchgear and a view of the Susquehanna River. 
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| (1276193) | |
Re: PHOTOS: SHOO FLY TWO |
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Posted by Jackson Park B Train on Wed Feb 19 01:21:56 2014, in response to PHOTOS: SHOO FLY TWO, posted by Jersey Mike on Wed Feb 19 00:38:55 2014. Thanks, nice reminders of an excursion in 62. |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by Bill West on Wed Feb 19 04:12:19 2014, in response to PHOTOS: SHOO FLY TWO, posted by Jersey Mike on Wed Feb 19 00:38:55 2014. The hoop things on the 138kV insulators are outlying spark gaps to supplement the lighting arrestors in the substations. They cut down the lightning strikes to something the arrestors can finish off.Looks like it was great day for a bike ride, thanks for the tour. Bill |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by chud1 on Wed Feb 19 05:33:42 2014, in response to PHOTOS: SHOO FLY TWO, posted by Jersey Mike on Wed Feb 19 00:38:55 2014. 5 drooling stars out of 5 drooling stars on these pictures and video's.chud1. :).... |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by Jersey Mike on Wed Feb 19 06:59:07 2014, in response to Re: PHOTOS: SHOO FLY TWO, posted by Bill West on Wed Feb 19 04:12:19 2014. Can you explain how the intermittent placement of metal hoop things hoops achieves the desired result? |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by TransitChuckG on Wed Feb 19 08:23:26 2014, in response to Re: PHOTOS: SHOO FLY TWO, posted by chud1 on Wed Feb 19 05:33:42 2014. Very nice work, Mike! |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by Mark S. Feinman on Wed Feb 19 13:22:36 2014, in response to PHOTOS: SHOO FLY TWO, posted by Jersey Mike on Wed Feb 19 00:38:55 2014. Thanks for that. I'll be putting this trail on my summer bike ride list.--Mark |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by Terrapin Station on Wed Feb 19 15:27:56 2014, in response to PHOTOS: SHOO FLY TWO, posted by Jersey Mike on Wed Feb 19 00:38:55 2014. Cool. |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by Jersey Mike on Wed Feb 19 16:18:14 2014, in response to Re: PHOTOS: SHOO FLY TWO, posted by Mark S. Feinman on Wed Feb 19 13:22:36 2014. You can get between the two halves of the trail (the A&S portion I was on is only about 10 miles round trip so you can do it in an hour or two) by carrying your bike down from the RoW to the Safe Harbor parking lot then back up the other side. |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by NJCL2308 on Wed Feb 19 17:00:18 2014, in response to PHOTOS: SHOO FLY TWO, posted by Jersey Mike on Wed Feb 19 00:38:55 2014. Pennsy Cat Poles awwww yisssss. |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by monorail on Wed Feb 19 20:40:18 2014, in response to PHOTOS: SHOO FLY TWO, posted by Jersey Mike on Wed Feb 19 00:38:55 2014. thought perhaps u posted to the wrong forum…. |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by Bill West on Thu Feb 20 01:42:46 2014, in response to Re: PHOTOS: SHOO FLY TWO, posted by Jersey Mike on Wed Feb 19 06:59:07 2014. I'm mistaken about lightning arresters, there are none on the transformers which is now unusual. Likewise there are none at the line entry into the station which had been an earlier practice. From the Railway Age feature on PRR electrification, Feb 25, 1933, pg 293:"Primary lightning protection for 132,000-volt transmission lines is insured by the ground or static wire run along the tops of the transmission line poles or columns. No transmission line lighting arresters are used except at the D1 substation (Zoo). The 132,000-volt circuits at the substations are protected from lightning or high-voltage surges in two ways. At the first pole on either side of the substation, one strain insulator string is reduced to 7 units instead of 13, and arcing or grading rings are placed around the two end units of the string. Any high-voltage surge originating on the transmission line will arc over at this point; the rings serve to protect against insulator breakage caused by (the instant heat of the) flashover. In addition bushings (on transformers) are provided with protective spark gaps (top/bottom pointer like rods). Transformers have 154kv class insulation. Lightning poles are used for protecting the substation. They extend above the substation structure to points high enough to protect all apparatus; each foot in height above the structure serves to protect to protect a circle of three-foot radius. Where possible, the lightning rods are mounted on the same structure which supports lines and switches. The poles are run from the ground when the desired location does not conform with the location of the substation structure. Experience thus far has indicated that trouble due to lightning is less frequent on the 132,000-volt line than it is on 44,000-volt lines." Your picture shows that there are more insulator discs in the string now. I'd have to look at Safe Harbor pictures to see if they changed the methodology to modern lightning arresters on the transformers. For background, insulation will withstand substantial short term overvoltages just as conductors withstand short term overcurrents. The difference is that the overvoltage time limits are measured in micro seconds. PRR's 154kv insulation has what is called a Basic Impulse Level of likely 750kv, that's what it will withstand when hit with a transient that rises in 1.5 usec and decays 50% in 40 usec. The insulation strengths are usually graded across the equipment so that the permanently damageable, costly equipment is protected by short circuiting flashovers at simpler equipment. The air around lines is particularly cheap and self heals almost instantly. When the gap in your picture flashes over the voltage drop across it is only 10's of kv thus protecting downstream equipment. A time allowance for the gap to react is all that is needed in setting the downstream strengths. The longer catch is that the regular 25hz power sees the arc as a short too, flows through it and unlike the lightning does not turn off when the lightning stroke finishes discharging. The line circuit breakers will have to open for a few cycles to let the ionized air float away. An automatic or manual reclose then restores service. The sort of protective relays that detect these shorts and reclose the circuit became my career. Next week we'll do Circuit Breakers 101 and Transformers 102, don't forget to send your tuition fees in :). Bill |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by SelkirkTMO on Thu Feb 20 03:00:34 2014, in response to Re: PHOTOS: SHOO FLY TWO, posted by Bill West on Thu Feb 20 01:42:46 2014. Heh. Have an apple, yo! :) |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by Dyre Dan on Thu Feb 20 06:09:14 2014, in response to Re: PHOTOS: SHOO FLY TWO, posted by monorail on Wed Feb 19 20:40:18 2014. Why is the type of thing in the pictures called a "Shoo Fly" anyway? |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by Jersey Mike on Thu Feb 20 09:26:23 2014, in response to Re: PHOTOS: SHOO FLY TWO, posted by Dyre Dan on Thu Feb 20 06:09:14 2014. It's technically a "flume", but a few books described them as Shoo Flys so that's the term I got in the habit of using. |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by Jersey Mike on Thu Feb 20 09:30:14 2014, in response to Re: PHOTOS: SHOO FLY TWO, posted by Bill West on Thu Feb 20 01:42:46 2014. The PRR did not use circuit breakers on its 132kV circuits. All the breakers were located on the 11vK side.Thanks for the explanation tho. That makes perfect sense now. |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by Bill West on Thu Feb 20 13:08:33 2014, in response to Re: PHOTOS: SHOO FLY TWO, posted by Jersey Mike on Thu Feb 20 09:30:14 2014. PRR breakers -yes, saving the substantial cost of high voltage circuit breakers by switching lines from the low side of the transformer was a smart idea that PRR lead in adopting. There would be lots of line faults that could be cleared from the high or low side but only a few transformer faults that would need clearing from the high side. So omitting the high side breaker and momentarily taking the whole line out for those cases would be sufficient. This is the same as the way that main circuit breakers on EMUs were replaced by pantograph grounding switches and opening of the cat circuit breaker back at the substation. Our western utilities did the same thing with smaller substations on 60 & 138kv transmission routes complete with a spring operated grounding switch to signal the need to trip back to the source substation.I think you know that originally the only 132kv breakers on the PRR were at Zoo, Perryville and Thorndale. I find them a novelty because they are 2 pole instead of the 3 that every other transmission breaker in the country is. And also because they have survived for 80 years, one doesn't see many higher voltage bulk oil circuit breakers any more. Nowadays Amtrak has included 132kv breakers at Jericho Park and indoors at Richmond SFC. Bill |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by Mark S. Feinman on Thu Feb 20 13:45:49 2014, in response to Re: PHOTOS: SHOO FLY TWO, posted by Jersey Mike on Wed Feb 19 16:18:14 2014. Excellent. Thanks!--mark |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by Jersey Mike on Fri Feb 21 07:48:48 2014, in response to Re: PHOTOS: SHOO FLY TWO, posted by Bill West on Thu Feb 20 13:08:33 2014. Interesting, I never noticed the 138vK breakers at those locations. |
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Re: PHOTOS: SHOO FLY TWO |
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Posted by Bill West on Fri Feb 21 10:50:13 2014, in response to Re: PHOTOS: SHOO FLY TWO, posted by Jersey Mike on Fri Feb 21 07:48:48 2014. Each 132kv breaker is a pair of 4-5 ft oval diameter, 8-10 ft tall oil filled tanks painted dark green with a pair of transformer style bushings sticking out of the top of each tank. In the aerial views they almost get lost under the pair of low isolating switches close on each side of them. Each station's breakers are under a gantry at the center of the property. I think all were made by Westinghouse.Jericho's are similar but painted light grey, one is under each outgoing line and the 3rd is under the cross bus between them. Richmond's switchgear is gas filled and is in the long metal building north west of the converter/transformer building. Bill |
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