Western Railroad Discussion > Alignment control couplers - who does what to whom?

I know that most road power has alignment control couplers. I know that some small switchers do not. I know that smaller switchers, like an SW-1000, et. al. are equipped with MU control. This suggests that MU consists of the small power were planned for. Alignment control couplers and non-alignment control couplers don't always play nice together. QUESTION #1: Four (4) SW-1500 locomotives, all with non-alignment couplers, can work together, true? QUESTION #2: An SD-40-2 with alignment control couplers and 2 or 3 SW-1500 units with non-alignment couplers - can the power all be operated together if the coupler on the offending locomotive, coupled to the SD-40-2, is blocked?

John Gezelius
Tustin, CA

john1082 Wrote:
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> QUESTION #1: Four (4) SW-1500
> locomotives, all with non-alignment couplers, can
> work together, true?

Yes. Locomotives with alignment control and non-alignment control couplers will work together just fine. There are no MU issues with the two types of couplers.

> QUESTION #2: An SD-40-2
> with alignment control couplers and 2 or 3 SW-1500
> units with non-alignment couplers - can the power
> all be operated together if the coupler on the
> offending locomotive, coupled to the SD-40-2, is
> blocked?

Blocked or not: you can MU them all together.

The overarching issue with locomotives with non-alignment control couplers is when you place them in a consist with DB equipped units in the trailing position pulling a heavy train. When the engineer places the lead units into DB, slack can run in on the unit with non-alignment couplers and push the coupler into a sideways position and into the windsheet (damaging the coupler pocket & windsheet at the minimum). In extreme cases, the force of the trailing tonnage against the damaged coupler will be deflected outwards and quite literally 'pop' the switch engine off the rails and result in a 20 or 30 car pileup.

I might add that limiting blocks are a poor man's (or railroad's) solution to this problem and will do absolutely nothing for a SW1500 with 3 or 4 units in DB on one end and 14,000 tons slamming into the other.



Edited 1 time(s). Last edit at 09/26/11 19:00 by KD7ZST.

The rules used to say you could only have a max of 2 switch engine in a road consist.

They had to be equipped with blocking bars and pins have the blocking bars in place and locked.

If you had two road units, you could take one switcher, cut in behind the lead unit with the other road unit next to the train.
If you had three road units you would put the first switcher behind the lead unit, then a road unit, then a switcher and then a road unit against the train. That was it.

You would MU them just like any engine but turn their electrical selector switch to "Road" Automatic. There were 4 positions, Switch 1, Switch 2, Road Auto, Road Forestalling".

Hell, its been too many years since I had to pick one of them up. Oh, you had to isolate the road units, pushing against the switchers in a reverse move.

Now the OLD switchers, Alcos,BLH & FMs had to be towed dead in train. Their brake valves had to be wired down in the right position so they couldn't move and they had to be cut in 5 cars ahead of the caboose.


Nudge

Is this why you see BNSF trains with the switch engines DIC hurried in the train? I see this quite a bit around Spokane.
Kevin

Greetings
Is alignment control couplers the same as self aligning couplers?

KR

Alignment control couplers act as normal drawbars in draft (pulling or stretched) but "lock up" in buff (as when the slack runs in or it is shoving cars with a heavy enough load to compress the draft gear) making them become rigid. Alignment control couplers can (and do) cause derailments when shoving a heavy cut of cars through a sharp curve because the drawbar does not have enough travel with the locked up alignment feature.

Alignment control draft gear is present on later units. Older units such as switchers which need the drawbar travel use the "coupler stop blocks:" which can be folded down when needed to traverse sharp curves. A common "fix" to convert switchers to alignment control couplers is changing the coupler head to one with side lugs and welding stop blocks in the housing to accomplish the "alignment control" feature. This modification has been universally accepted by BNSF but not so much on UP but they are learning!

OPR has converted three units thus far and has worked out extremely well.

Dick Samuels
www.oregonpacificrr.com

FWIW, I saw SP trains with 4 SW1500s and a lot of cars going up the hill east of the City of Industry yard headed towards Pomona and probably West Colton. I presume they also came back down the 1+% grade.

mapboy

mapboy Wrote:
-------------------------------------------------------
> FWIW, I saw SP trains with 4 SW1500s and a lot of
> cars going up the hill east of the City of
> Industry yard headed towards Pomona and probably
> West Colton. I presume they also came back down
> the 1+% grade.
>
> mapboy


The all had the same draft gears, so that wasn't an issue.


If you saw 2, SD-45's and 3 1500's that might have been an issue.

mapboy Wrote:
-------------------------------------------------------
> FWIW, I saw SP trains with 4 SW1500s and a lot of
> cars going up the hill east of the City of
> Industry yard headed towards Pomona and probably
> West Colton. I presume they also came back down
> the 1+% grade.
>
> mapboy

But not a single dynamic brake in the consist. Engine brakes would not control much of a train so train brakes would be required with a heavy train, this would keep the slack stretched negating the lack of alignment control couplers.