?Tightest continious curve?

[Boyd]

Whats the tightest or smallest continious curve you have seen on a standard gauge railroad.

[Modelcar]

.....I'm sure you mean pure railroad track, but just a comment on still the same gauge rails of interurban / streetcar tracks.  That would be at a turning loop.  That radius was so sharp the trucks looked to be turned about as sharp as possible when they negotiated those turn-arounds.  I always wondered how they "bent" the rail so sharp" to construct those loops without "kinking" the rail.....

[mudchicken]

.....I'm sure you mean pure railroad track, but just a comment on still the same gauge rails of interurban / streetcar tracks.  That would be at a turning loop.  That radius was so sharp the trucks looked to be turned about as sharp as possible when they negotiated those turn-arounds.  I always wondered how they "bent" the rail so sharp" to construct those loops without "kinking" the rail.....

3 rollers and heat (still done today)

[mudchicken]

Main line would be about 23 degrees on the ex-Clover Leaf Maumee River Wye in Toledo (and the reason why becomes obvious)

In backtracks...... developers, architects and non-railroad consultants continue to ask the impossible.

[Paul_D_North_Jr]

R= about 150 ft.  = about 38 Degree curve (as determined by survey & "stringline" measurements) - in HO scale, this is about 21 inch radius (which is usually viewed as somewhat broader than "sharp" in the sharp [18" R] to broad [30+" R] continuum of curves.)

 On a cold, rainy day in March '76 or '77 I helped "shoehorn" a ConRail GP-38 (I think that's what it was) around this curve - at about 1 MPH - at the inner end of a run-around track at the Middletown East End Warehouse complex (a little south of Harrisburg, PA - real close to the soon-to-become infamous 3 Mile Island nuclear power plant).  It had become "trapped" by a comparatively minor derailment of a couple of its cars behind it, and this was the only was to get it out and back into service promptly, without waiting for the cars to be rerailed and the track repaired - probably a 2 -3 day process, between CR's carmen to do the rerailing and us to do the trackwork - so CR was real eager to have this done.  The survey measurements were done later in connection with a proposal to realign the curve to a less-sharp curvature (never done, though, as far as I know).

That said, this was only a small segment - 30 ft. or so - of that curve, and the track could definitely be seen to be sliding laterally in the ballast as the loco's trucks negotiated it.  I have no doubt that the loco was essentially realigning that curve as the loco needed the curve to be as it went.  The rain no doubt helped lubricate the wheel flange - rail interaction, too. 

More typically, this kind of curve was negotiated only by small industrial locomotives - 4 wheel "critter" types.  For curves routinely negotiated by full-size power, about 250 ft. radius = 23 Degree curve was about it - again, industrial and lightly used yard trackage only.

On the riverfront in Phila., I believe there were curves in the 150 ft. radius range, though I am subject to correction by someone with access to better information who might be able to confirm that.  These curves were typically too tight for the coupler side swing - they were switched by pushing the cars in, and pulling them out with chains.  Again, not normal anyplace but here.

- Paul North.

[CSSHEGEWISCH]

The Chicago Transit Authority is well-known for the 90-foot radius curves on the corners of the Loop L and a few other places.  In 2003, there was an easing of the reverse curves at Harrison where the L jogs from Wabash to a north-south alley.

[henry6]

NJT's HBLRT has some 90 degree turns in the length of a car...or at least they look that sharp!  PATH is noted for some of its sharp curves especially at interlockings but leaving Hoboken for 33rd St. itis almost a 180 within a quarter of a mile.  I think outside rapid transit, though, is what you are looking for here....here in Binghamton there is track 5 as it is called now, the former DL&W east leg of the wye or former S&U track now CP's D&H southbound main across the Southern Tier Line.  It does a 90 degree in less than a half mile.  5-10mph.

[Modelcar]

 

....Thanks for info on bending rail M C.  If anyone is interested to see what I was talking about in above post, go to search and put in "Johnstown Traction Co."......It was abandoned 48 years ago but you can find on a web site dozens of photos of it's operation.  Look thru and you can find a trolley on a turning loop to see how sharp they really were.

[henry6]

Ride NJT's Newark City Subway and HBLRT for tight loops,too.

[garyla]

As far as freight lines go, aren't some of those local tracks in the New York streets some of the tightest in the land?

[timz]

Not in use, but there's still at least one 40-degree curve into a factory here in Oakland. That's the sharpest I've seen personally, but for line-haul railroad curves in the past it would be hard to beat those oval Bronx freight houses on the DL&W and CNJ (and Erie?)-- the tracks inside the oval were about 90-foot radius.

I'd say new light-rail curves are usually not less than 100 ft radius, but the Newark City Subway curve at Penn Station is considerably less than that.

Sharpest streetcar curve I ever heard of was the one at the east end of Market St Philadelphia-- 24 ft radius.

[Ulrich]

Does HO scale count?

[Looshi]

There used to be a spur to a grain elevator in Lebanon Ohio that was real sharp. The track did a 90 degree turn in about 175 feet of track. The corner of the elevator was even built with a curved side just to fit the track in. The spur was laid down in the early 1900's so it wasn't designed for the real big stuff. An engineer I talked to called it "a real flange-squeaker".

It's gone now though, I think that spur was pulled up sometime in the 80's. A few of the rails are still there today though.

[Modelcar]

.....Along with the transit system I was {very}, familiar with back in Johnstown, Pa., we had a street system here in Muncie until 1931 {long before I was here}, and I've seen photos of the track being laid including at street intersections, and those really are 90 degree curves at such points.  I wonder what those radius curves would have been in figures....?

One can still see the imprint of buried rails in many streets around here.  Lots of city and interurban op around Indiana back in the heyday.....Large brick "car barns" here still exist.

[Railfan Alex]

There was an article in an MR special about the Harlem Transfer. The layout had 15 inch (HO scale!) radius, and apparently, the prototype was the same radius (or whatever that is in 1:1)Now that's tight!

[Wdlgln005]

Is the former WP branchline into Reno NV still in operation? IIRC it was too tight for six axle SD type units. I forget how many miles the line went from Reno to the mainline. When I was there, the UP used it for a small yard.

[CSXDixieLine]

I believe the sharpest mainline curve on the CSX system is the one on the north main track just east of the Hawks Nest trestle that crosses the New River. I am not sure of the exact degree of curvature, but CSX has been trying to figure a way to eliminate this curve for a while, including eliminating that track altogether. The photographer in this picture is standing right next to the curve in question:

Jamie

[timz]

Is the former WP branchline into Reno NV still in operation? IIRC it was too tight for six axle SD type units.

The 1974 track chart shows nothing sharper than 12 deg 30 min, except right where they joined the SP which was 20 degrees. But looks like they've broadened that curve since then.

 

I believe the sharpest mainline curve on the CSX system is the one on the north main track just east of the Hawks Nest trestle that crosses the New River.

The 1960s chart shows it as a 9 deg 54 min, so nothing special. For all I know that might have been the sharpest curve on the C&O main-- but the Clinchfield still has 14-degree main line curves, doesn't it?

[CSXDixieLine]

Hmmmm...you know I have heard at several different times that the Hawks Nest curve was the sharpest on any CSX mainline, but never thought to actually look it up. You are correct it is only a 9 deg 54 min curve in more recent track charts also, and there are several former Clinchfield curves that exceed that. Jamie

[wccobb]

The EMD Operating Manual for the 600 & 1000 H.P. Switching Locomotives (Operating Manual No. 2303, Models SW-1 & NW-2) under "General Data" shows Minimum Curve Radius for all units of 100 ft. (page 13).

The EMD Operating Manual for Model F3, (Operating Manual No. 2308A) under "General Data" shows Minimum Curve Radius of 274 ft.   

Not strictly to the point, but perhaps of interest anyhow.

[Modelcar]

....I just happened to remember we have a very tight curve on the NS here in Muncie.  I don't have the figures but it's location is the transition from the NewCastle line to the Frankfort line.  For anyone caring to take a look via satellite or in written specs, etc....I'm referring to the curve off the NewCastle line into Muncie from the south and curving to the west to go across {Diamonds at CSX}, to direct it to the Frankfort line...{northwest}. 

I'd be interested to find out just what those curvature figures really are.

I don't have such data.

[rrnut282]

MC

That curve may not be as bad as you think.  The ETT lists a 25mph restriction from MP CF 119.8 (6th St Interlocking) to MP CF 123.2 (North of BATH interlocking).

The same timetable lists a 15mph restriction from MP CF119.8 (6th St again) to MP SP 174.3 on the Frankfort District Connection Track going West.

It doesn't give degree or radius, but it would appear the through route for New Castle District trains isn't as sharp as the route trains to/from Frankfort have to take to/from Cincinatti.

[tree68]

There's a pretty sharp curve on the old Erie in Hancock, NY.  Between that, the old truss bridge, and a half dozen crossings in a half mile, they pretty much crawl through there.  I know a couple of people who don't appreciate the squealing after a night of imbibing....

[mudchicken]

The EMD Operating Manual for the 600 & 1000 H.P. Switching Locomotives (Operating Manual No. 2303, Models SW-1 & NW-2) under "General Data" shows Minimum Curve Radius for all units of 100 ft. (page 13).

The EMD Operating Manual for Model F3, (Operating Manual No. 2308A) under "General Data" shows Minimum Curve Radius of 274 ft.   

Not strictly to the point, but perhaps of interest anyhow.

274 FT is a tad over 21 degrees of curvature (21d-01'-43"; 100ft is a 60 degree curve))

It's one thing if its just the locomotive in the curve, quite another if it's coupled to another locomotive or car (then coupler swing and drawbar forces come into play)

[timz]

very tight curve on the NS here in Muncie.

If you mean this one http://tinyurl.com/5nbjos it looks to be no sharper than 12 degrees-- likely 10.

[Modelcar]

....Mike, yes that curve on the connection and then crossing of the diamond to get across CSX is the location I spoke of.  15 mph is rather slow....I know, looking at it from ground level it sure made me take notice....It passes rather close to some buildings there.

 

[Modelcar]

....With a 15 mph restriction around that area It has some meaning of curvature.  It certainly does take one's attention looking at it from ground level.

That Google map photo of that area....has the Cardinal Greenway marked incorrectly.  If one starts at the {reddish roof depot...clay tile, just to the left of Broadway}, and follows the trail north from there for the next half mile or so it is marked wrong.  Actually the trail is to the left of where it is marked.

[trainfan1221]

Tree, I know where you mean, but I've never read about the curve there being too bad.  Either way there aren't enough trains there anymore to bother anyone!