Author Topic: Gravity Switching - A Grave Mistake  (Read 14133 times)

john d Stone

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Gravity Switching - A Grave Mistake
« on: May 11, 2014, 10:31:32 PM »
This may be an unthinkable option in these times, but I was wondering if the main line grade is steep enough to reliably execute a "static drop"?
I bet that's what they would have done, back on the original W.W.&F. That would eliminate the need for the crossover and provide a very realistic demonstration.

Just a thought.
« Last Edit: May 12, 2014, 05:06:09 PM by Ed Lecuyer »

James Patten

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Re: Gravity Switching - A Grave Mistake
« Reply #1 on: May 12, 2014, 07:04:10 AM »
Not sure what you mean by a static drop, but if you mean letting gravity do the work of switching, that would be a big NO!  We've got hand brakes, not air brakes or retainers.  If we're unable to stop the train at the top of the grade, it won't get any easier to do and we'll end up with a runaway train.  Not acceptable with passengers.

Glenn Christensen

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Re: Gravity Switching - A Grave Mistake
« Reply #2 on: May 12, 2014, 12:07:19 PM »
Not sure what you mean by a static drop, but if you mean letting gravity do the work of switching, that would be a big NO!  We've got hand brakes, not air brakes or retainers.  If we're unable to stop the train at the top of the grade, it won't get any easier to do and we'll end up with a runaway train.  Not acceptable with passengers.

Hi Guys, 

I think you guys are referring to gravity switching.  This was practiced regularly at Bridgton Jct by the B&SR and still daily today at the Taurachbahn in Austria https://www.youtube.com/watch?v=RmfQ_mdFzNY.  (See starting at 2:30)

As you can see, the practice can be done safely and works fine, but the operational conditions must be carefully controlled and the whole maneuver is performed at a dead slow pace.

At both the Jct and in Austria, the physics of the gravity grade were carefully engineered and the gravity downslope was/is followed a long level, or slightly upgrade, roll-out section.  At Bridgton Jct. the approaching downgrade was a long stretch of two percent, so to be safe, the engineers added a short sharp opposing grade immediately after the gravity slope so crews could better control the roll-out.  This opposing "speed bump" can be seen in Steve Hussars excellent video on the B&SR.

In the case of TOM, northbound trains are already coming down a steep grade, the level section is very short, and it is followed by an even more serious downgrade.  So in this instance, gravity switching would not be safe.


Best Regards,
Glenn

Wayne Laepple

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Re: Gravity Switching - A Grave Mistake
« Reply #3 on: May 12, 2014, 12:43:00 PM »
I may have already mentioned this, but in its early excursion days, the Strasburg Rail Road used gravity switching to get the train around the locomotive at Leaman Place Jct. They would back the train up onto the old interchange track, cut the engine off and pull into the clear on the main line before allowing the cars to roll past the engine. Later, when the train grew longer and they had a steam locomotive, they would station their 44-ton GE diesel at Leaman Place to pull the train by after the steam locomotive cut away and backed into the original interchange track.

A shortline in South Carolina, the Pickens Railroad, did not have a runaround track anywhere on its line, depending entirely on gravity to get cars around the locomotive at both ends, and I saw the crew also coast cars into an industrial siding.

When I worked for the Maryland & Delaware RR in Maryland in the early 1980's, we regularly dropped cars out of sidings using only their handbrakes.

I would note that in none of the cases cited above was the actual work done by amateur or part-time railroaders. You had to keep your mind on your work and pay attention at all  times.

Allan Fisher

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Re: Gravity Switching - A Grave Mistake
« Reply #4 on: May 12, 2014, 03:27:18 PM »
As former System Director of Operating Rules for Conrail - I am appalled at the suggestion of "dropping" any kind of cars. The big railroads always had a complete prohibition on dropping of passenger cars - whether occupied or not, and after I and others developed the NORAC rulebook - we prohibited "dropping" of any cars at any time.

The accidents I can relate would fill a large notebook because of this very bad practice.
Allan Fisher

Wayne Laepple

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Re: Gravity Switching - A Grave Mistake
« Reply #5 on: May 12, 2014, 04:47:52 PM »
I witnessed Conrail crews dropping cars on a fairly regular basis at several locations on the Buffalo line and nearby industrial tracks.

One more story. The Gettysburg Railroad, operated by a family, used to back its one-car train into a siding and tie on a handbrake. The engine would then pull out onto the main and back up parallel to the car. Then the engineer would climb down and reline the switch before dropping the car onto the main track. The engineer, by the way, was the only member of the engine crew -- no fireman, and often the conductor was one of the engineer's teenage grandkids.

I do not advocate any of these practices; in fact I agree 100% with Allan. Flying switches and dropping should be strictly forbidden.
« Last Edit: May 12, 2014, 04:49:58 PM by Wayne Laepple »

Ed Lecuyer

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Re: Gravity Switching - A Grave Mistake
« Reply #6 on: May 12, 2014, 05:12:21 PM »
[Mod's Note]
It is important to note that while dropping cars using gravity and not locomotive power/flying switches, etc. may have happened historically by the original railroad, such movements are not permitted at the WW&F Railway Museum.
« Last Edit: May 12, 2014, 07:29:15 PM by Ed Lecuyer »
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Keith Taylor

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Re: Gravity Switching - A Grave Mistake
« Reply #7 on: May 12, 2014, 05:13:21 PM »
I know I was very surprised to find that Railways in the UK had what they called "slip coaches" that they would cut off of a moving train to coast into the station no longer coupled to the train. The train would continue at speed and a train crew member would stop the coach at the platform.

http://railwaywondersoftheworld.com/slip-coaches.html

Keith
« Last Edit: May 12, 2014, 05:33:33 PM by Ed Lecuyer »

Allan Fisher

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Re: Gravity Switching - A Grave Mistake
« Reply #8 on: May 12, 2014, 06:33:25 PM »
In the early 70s, Penn Central built their hotshot Piggyback trains (SV6, 8 & 10) departing Chicago with a caboose on the East of Cleveland portion of the train and another caboose on the Cleveland set out at the rear of the train. While pulling into one the the Fast Freight tracks at Collinwood Yard in East Cleveland, a yard conductor would climb aboard the cut-in caboose, and a brakeman would run alongside the "pin" and call the engineer of the inbound train for a "little slack" and pull the pin and tell the engineer to pull ahead. The rear block would then (with closed angle-cocks) drift into the adjacent fast freight track. The through train inbound crew and outbound crew would then change "on the fly" at about 4 - 6 MPH, and depart without ever stopping.

This practice went on until early Conrail days when a conductor making the move was killed. This ended the practice that management had allowed with a "blind eye"
Allan Fisher

John Kokas

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Re: Gravity Switching - A Grave Mistake
« Reply #9 on: May 12, 2014, 06:44:55 PM »
As a former short line operator myself, I have to agree with Allan on this one; there should NEVER be gravity / on the fly / drop switching on the WW&F.  It is just too dangerous for an experienced crew and for volunteers is just an accident waiting to happen!  IMHO - the BOD needs to put an end to any idea of this.

Mike's plan is reasonable to construct and safe to operate on, let's stick with what he proposes.
Moxie Bootlegger

James Patten

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Re: Gravity Switching - A Grave Mistake
« Reply #10 on: May 12, 2014, 07:17:07 PM »
the BOD needs to put an end to any idea of this.

There has never been any idea of this happening.  The idea of doing it originated here on this forum!

Ed Lecuyer

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Re: Gravity Switching - A Grave Mistake
« Reply #11 on: May 12, 2014, 07:33:37 PM »
[Mod Note, again]
This topic is to discuss the historic practice used by railroads in the past (and in some cases present) of dropping cars, gravity switching, and the like.

There is no discussion about this practice occurring at the WW&F Railway Museum. Present or Future. This practice is forbidden by our rule book, and has never occurred on the (modern) WW&F.

That said, I do want the conversation to continue about this type of movement, but in the context of what is/was done elsewhere - mostly because I think it is interesting and not because I think it is relevant to the WW&F museum. (Thus, it is in the "General" discussion section.)
« Last Edit: May 12, 2014, 07:37:11 PM by Ed Lecuyer »
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Glenn Christensen

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Re: Gravity Switching - A Grave Mistake
« Reply #12 on: May 13, 2014, 12:46:19 AM »
Gentlemen,

Per Ed's most recent note, I was explaining the concept of gravity switching in response to John Stone's innocent question.  I was not advocating the practice and I believe John was simply "wondering" due to its use on the original WW&F.

Wayne too was, I think, simply seeking to exemplify the concept and I learned some new information thanks to his posting.  I also learned more from Alan's response.

Please do not read into these posts more than what was intended.


Sincerely,
Glenn

Philip Marshall

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Re: Gravity Switching - A Grave Mistake
« Reply #13 on: May 13, 2014, 03:00:32 AM »
In addition to the B&SR, the SR&RL also appears to have employed "flying switch" movements on occasion. The "Sandy River Line" DVD of 1930s film footage by Newell Martin, which is sold by the SR&RL group up in Phillips, includes a short but amazing sequence in which SR&RL #18 (if I remember correctly) is moving northbound into Phillips yard with combine #11, and the engine pulls away into the roundhouse lead while the combine continues up the main by inertia and is brought to a stop in front of the Phillips station with just handbrakes, all in a single continuous movement. However, this was all done on level ground and so is quite different from "gravity braking".

One of the more dramatic historical examples of the "flying switch" I've heard about was on the Long Island RR in the early 1900s, in which eastbound express trains from New York City to resort towns on eastern Long Island in the summer season would be split into two sections in Manorville, NY (which is about 15 miles from my home): the engine and the front half of the consist would continue on the main line to Greenport, NY without stopping, while the rear half would take the line to Montauk, NY and couple onto a second engine that was already accelerating away from the junction! This was all supposed to be done at speed and in such a manner that the passengers were unaware of what had occurred. Not safe at all, but I'm sure it must have been amazing to witness.

-Philip Marshall

john d Stone

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Re: Gravity Switching - A Grave Mistake
« Reply #14 on: May 13, 2014, 09:57:43 PM »
I was "off the grid" for a couple of days (actually, away from my home computer and unable to fathom my password), it would appear I created quite a fire storm. Geez! I feel like I wore white after Labor Day, or something!

Really, the prospect of dropping loaded passenger cars down a 3% grade towards a big washout was not what I intended. Lets leave that for space mountain or Universal Studios. My thought was to leave the cars on the main, drop the engine down the main and reline the switch for the TOM siding, which appears flat or slightly uphill, and drift the cars into the siding. No way would I allow passengers to occupy said consist during the move. I considered, perhaps "skates" as a safety brake a couple of carlengths from the north end of the siding. These are devices placed on the rail in humpyards to keep cars from running out of a track, which look like a steel chock with a long flat surface on the rail. When a car encounters a skate, the lead wheel rides up on the flat and shoves the skate which slides on the railhead, acting like a brake. They really work well. But, I understand that the prospect of doing this with irreplaceable museum equipment raised a few objections. I get that. Perhaps I should stick to stories about rubber ducks!

Anyway, extending the railroad to TOM and beyond is an exciting prospect and I look forward to my next visit when I can offer limited skill and a weak back to a truly talented and energetic group of people. I promise to only allow gravity to effect my misguided hammer blows!

John