Wayward yard switcher units

[beaulieu]

Can someone please explain self-aligning couplers, or the lack of, and how that would cause a derailment? Thanks

Murphy, couplers are attached to the locomotive with a pin through the shank around which it has a degree of freedom to pivot. When a train is in dynamic braking or the Engineer is using just the locomotive brakes to slow the train, the train pushes on the locomotives, this produces a “Buff” force and this force is greatest on the couplers between the last locomotive and the first freight car (or dead locomotive). On a locomotive without Alignment control couplers the coupler can pivot quite freely and over a greater arc of swing. On a locomotive with Alignment control the free swing is over a much small arc, and the remaining portion of the swing has a resistance built in so that it can swing over that greater portion, but not freely. To understand what’s happening consider a handstand, it is easy to do with your elbows locked (or was when I was younger), but difficult with your elbows slightly bent. With the couplers deflected more than slightly from straight, the buffing force induces a twisting pressure on the freight car, which when it reaches a great enough amount will force the car off the outside of a curve. This is a reasonably common occurrence when a train experiences an emergency brake application while rounding a curve, especially if the cause of the emergency application is near the front of the train as the momentary forces from the slack running in will be of a much higher magnitude than the sustained buffing force of a dynamic brake application.

Now road locomotives have dynamic brakes and are normally used on mainlines where curves of tighter than 10 degree are rare. Switch locomotives are much rarer on mainlines but are commonly used on Industrial trackage where curves up to 20 degrees are not uncommon. Because of the sharper curves their couplers need to pivot more.

[Paul_D_North_Jr]

First, anything I say here is subject to amplification and correction by a real Mechanical Dept. person or someone with equivalent expertise. I’ve tried to find a decent illustration or photo of this ‘on-line’ but no luck with that so far.

That said, I believe it’s more about the coupler shank, than the coupler knuckle itself. Specifically, on road locomotives there are usually pretty tight mechanical limits on the amount that the coupler shank can swing from side to side - even on curves - because most road locomotives don’t get into very sharp curves very often, say maybe a 10 to 12 degree = 573 ft. to 477 ft. radius, respectively.

However, switchers are different - sometimes they’re on curves as sharp as 23 degrees = 250 ft. radius, esp. in old towns and tight quarters, or branch lines in the mountains, etc. Since the couplers mounted on the end of the frame, they extend beyond the wheelbase. So when uncoupled, the couplers are usually pointing straight ahead, which would be towards the outside of the curve. But when coupled to another car or locomotive, the couplers have to have an angle back in towards the center of the curve in order to mate with the other coupler. The sharper the curve, and the longer the wheelbase of the locomotive or the attached car, the sharper that angle is. That coupler angle can get really extreme and odd - and/ or maybe even go the other way, towards the outside of the curve, if the attached car has a comparatively long extension of its frame and coupler beyond its truck centers, which would put its coupler even further outwards on the curve than the switcher’s. So that’s why the switcher needs to have a pretty flexible coupler, one that can swing pretty far from side to side.

However, when the switchers are coupled together - as apparently happened here on the CSX train - the

[The_Butler]

Don’t rail car knuckles have as much swing as the switcher’s? [%-)]

[mudchicken]

Absolutely not…

Restrictive coupler swing gets really nasty with passenger units. Then figure in the distance from the coupler to the kingpin of the powered trucks and you get a really wicked lesson inexcessive lateral force on the rail. If those forces get too extreme, either the rail gets rolled over or the cars break/derail. (Something has to give)

On old ATSF rebuilt GP-7s and GP-9’s, a pair of triangular blocks were welded on the face of the locomotive coupler pocket that the drawbar rests in to remedy the switcher vs. road unit issue. A big, removable pin similar to a knuckle pin rode in a hole in the drawbar and swung between the two triangular pieces. If you needed extra turning ability, the switch crew raised the pin above the triangular piece and then dropped it back in when they straightened out. This cut the coupler swing down to about 18 inches. (I never saw a working SSB-1200 or NW-2 in my Santa Fe career, the Beep never left the shops - ATSF got rid of excessive curvature at every opportunity. They leased an SW-900 (#1453 IIRC) to a SE Ks refinery until it went under or got rid of the stupid sharp curves from inside the plant…at the end of ATSF, the “Beep” was the last end cab switcher. UP did something similar…)

The limited coupler swing issue drives roadmasters nuts. If you had # 6 1/2 and/or #7 turnouts where certain units went, you worked many nights cleaning up the damage caused by the locomotives, usually big GE’s that were the worst violators by far (something like a 7" coupler swing vs. 26" on an SD40-2, Amtrak P42’s had it down to about 5 1/2 inches.)…

Have a # 6 1/2 turnout in an engine facility designed for small engines (end cab switchers) and now handling road units, soak the ties with spilled diesel fuel so the spikes will no longer hold and you spend many a night repairing destroyed turnouts with clueless operating and mechanical supervisors

[wabash1]

Nice try but the dynamics are not going to cause me a problem if that was the case then they empty car blocks on the head end of a 9k ton train would kick out also. so not buying it. those engine made it there with out any problem so why that section of track then blame the engines

So what does the NS rule book say about dynamic braking when you have NS 8000 series locomotives in the power consist. On CP if you have more than two AC units on a train with headend power only you have to begin cutting out dynamic brakes, unless the train is a loaded bulk unit train, then three are allowed. Are you trying to tell me that NS has never experienced a car being ejected from the train due to bad train handling causing excessive buff forces?

I agree about engines consist we have something like that here on the NS. well i hope we can get a answer to the problem , these little engines was going i thiink i can but in reality they realy said I think i did it now.

Most people seem to think that NS has earned its unsavory sobriquet from paying more than lip service to the rule book.

What does 8000 series haft to do with it? if you must know its not from the book but from knowing the book 8700-8800-8900-9000and on up to 9900 are all ge engines and can only have 2 engines on line for dynamic. I see where you mention something about AC traction motors same things 2 units on line for dynamic.

[rrboomer]

You’ve obviously never been a party to

All i can say is CSX is a liar, Prove to me that the little 1500 thats pulled 3-4 decades of switching in sharp curves that your common gp 38 cant enter in curves that the big 6 axel is limited to 10 mph due to the radius of the curve and how non-self aligning draft gear caused this. this should be interesting.

the embarrassment that buff forces on three or more non-self aligning coupler units at rear of consist can inflict.

[blue_streak_1]

Train in heavy dynamic braking at the time perhaps? Train speed in the Twenties, a fairly heavy train behind, and five short switchers all coupled together right behind the power, is a nasty combination if the Engineer makes a heavy application of the dynamics. I know some Class Is require that limiter blocks be installed before locomotives that lack Alignment Control couplers will be moved.The blocks prevent the couplers from swinging too far off center. The advent of modern high-capacity extended range dynamic braking coupled with AC motored power made proper train handling in braking, just as critical as the handling in power.

CP requires that a locomotive not equipped with Alignment Control couplers be moved as part of the locomotive consist between two locomotives that are equipped. So when CP moves an MP15AC from Chicago or Milwaukee to St. Paul for shopwork it is always sandwiched in the middle of the power consist.

Beaulieu: Specific power set up is unknown but I will give you a general operational overview how most trains are handled.

1. Coming off the old ACL Linville sub at CP LaGrange onto the A&WP sub trains are limited to 25 MPH and are going slightly down hill around a tight curve to the left.

2. When 1/2 of the train clears CP LaGrange the engineer will throttle up for a 45 MPH allowed speed going slightly up hill on either of 2 main tracks.

3. AT about 1-1/2 mile is the slight right hand curve where the SW1500s derailed. At that point the engineer will see a CP that is about 2 miles North (east) of LaGrange CP. This is CP LaFayette Connection where the 1 track A&WP splits straight northeast and the 2 track ACL lines go to the right on a slight curve to the ESE.

4. The next CP (JR Mapp) is only about 7/10 of a mile and if the signal as the

[alcodave]

All i can say is CSX is a liar, Prove to me that the little 1500 thats pulled 3-4 decades of switching in sharp curves that your common gp 38 cant enter in curves that the big 6 axel is limited to 10 mph due to the radius of the curve and how non-self aligning draft gear caused this. this should be interesting.

Wabash, What was the rule on Norfolk Southern and NW about the self aligning couplers? Units with White stripes under the number? I heard something about it once, don’t remember the details though. could this have caused a derailment? Is that still a NS rule?

[wabash1]

All i can say is CSX is a liar, Prove to me that the little 1500 thats pulled 3-4 decades of switching in sharp curves that your common gp 38 cant enter in curves that the big 6 axel is limited to 10 mph due to the radius of the curve and how non-self aligning draft gear caused this. this should be interesting.

Wabash, What was the rule on Norfolk Southern and NW about the self aligning couplers? Units with White stripes under the number? I heard something about it once, don’t remember the details though. could this have caused a derailment? Is that still a NS rule?

I am know what your saying and i dont recall the rule either and i dont feel like looking it up. Mud chicken the only car i know in frieght service that has as much drawbar movement as those so called engines are the autoracks. so if these engines cause this micj problem then we should be throwing racks out right and left heck i have 75 at a tome never kick one out, ive had five on the head end and then trailing with 10100 tons and never kicked one out even with 3 big units in dynamic. ive had several of these (3 in tow) and never had a problem NS has these little engines that could ive switched with them . I got to hand it to them they can move some tonnage cant stop it but it can move them.

In my post it says prove it to me, i can see what you guys are saying but not quite got me convinced, like ive said ive had these in my consist and no problems . Oh and if you have not figured it out No i dont know the answer never did that is why I said prove it to me. Paul what you posted is logical, just not commiting yet let me sleep on it.

[oltmannd]

First, anything I say here is subject to amplification and correction by a real Mechanical Dept. person or someone with equivalent expertise. I’ve tried to find a decent illustration or photo of this ‘on-line’ but no luck with that so far.

This is the best I could find.

http://www.wikipatents.com/US-Patent-3827575/method-and-apparatus-for-providing-coupling-train-action-and-alignment/Page-3

The feature to look at is the ears on the butt end of the coupler. When in buff, they tend to keep the coupler centered.

[Paul_D_North_Jr]

OK - thanks much for that link, Don [tup] - that makes sense.

Below are some excerpts from the NS-1 - RULES FOR EQUIPMENT OPERATION AND HANDLING - EFFECTIVE: OCTOBER 1, 2007, pages 55 - 56 [pages 63 - 64 of 143 from the ‘PDF’ format version], from - http://www.yardlimits.com/forums/downloads.php?do=file&id=37&act=down - that pertain to this [emphasis added - PDN]:

L-212. ALIGNMENT CONTROL DRAFT GEAR

When the locomotive consist includes more than one unit that does not have alignment control draft gear (see Rule L-214), extreme caution must be exercised when applying locomotive or dynamic brake or handling the throttle in back up or shoving movements to prevent units from jackknifing.

L-213-1. TOWING AND PUSHING SW1500, SW1001 AND MP15DC LOCOMOTIVES

[wabash1]

[quote user=“Paul_D_North_Jr”]

OK - thanks much for that link, Don - that makes sense.

Below are some excerpts from the NS-1 - RULES FOR EQUIPMENT OPERATION AND HANDLING - EFFECTIVE: OCTOBER 1, 2007, pages 55 - 56 [pages 63 - 64 of 143 from the ‘PDF’ format version], from - http://www.yardlimits.com/forums/downloads.php?do=file&id=37&act=down - that pertain to this [emphasis added - PDN]:

L-212. ALIGNMENT CONTROL DRAFT GEAR

When the locomotive consist includes more than one unit that does not have alignment control draft gear (see Rule L-214), extreme caution must be exercised when applying locomotive or dynamic brake or handling the throttle in back up or shoving movements to prevent units from jackknifing.

L-213-1. TOWING AND PUSHING SW1500, SW1001 AND MP15DC LOCOMOTI

[Paul_D_North_Jr]

This afternoon at 1500 in LaGrange Ga there were 5 TRRA switchers parked on a siding. The units appeared in good condition coupled together with air hoses connected but MU cables not connected. The unit numbers were 1511, 1508, 1505, 1503, 1506.

The units were parked on what is known as the Dunsden lead (part of the old ACL main BHM thru LaGrange - Manchester that was downgraded when the ACL line was combined with the A&WP line in LaGrange). This is not a normal location to park bad order cars. There are no scrap dealers around LaGrange either. The location makes it impossible to determine which main the units traveled on however they probably either went east (TT south) on the Manchester Sub or north on the A&WP sub.

Yesterday while looking for photos for another ‘‘couplers’’ thread here, I stumbled across these really good photo of the subject units - none of these are mine, of course - apparently taken just 6 days after the Original Post above - at the same or a nearby location. I’d say this illustrates quite well the hazard of couplers without the ‘alignment control’ swing limitations !

http://www.railpictures.net/viewphoto.php?id=318909