How does the MU coupler work?

[train2]

Had the opportunity to observe a SEPTA MU car's coupler up close, this was one of the older cars not the new 5s or whatever they are called. Having never paid a lot of attention to these things before I see there appears (when looking at the uncoupled end) to be a male and female pin or rod that slides into the coupling mechanism in a side by side arrangement. What struck me as odd was of the pin that stuck out on the male side there seemed to be no notches to catch anything on the receiving end of the opposing car. It was a smooth round pin/rod. So how does the car "lock into place" so that it doesn't come apart? Did I miss a notch on the underside? I did not climb down out of my engine.

It also appears they do not use air lines between the cars when coupled so I take the brake commands are electrical in nature. I also did not note any type of uncoupling lever to cut the cars loose when coupled. However I was more intrigued at the operation of the pins that I did not take full notice of a cut lever.

Anyway any help is appreciated. I make lots of coupling but never had to deal with one of these. In the past a have seen the adapter to mate with an AAR coupler but this car did not have one for added observation.

What is the proper name for this coupler on the MU cars?

[glennk419]

The official designation for the couplers on the SLIV's is a N-2-A semi-automatic coupler. The spears have a notch cut into them which is engaged by a latch mechanism in the coupler head. The coupler head also contains two pneumatic ports for main reservoir and trainline air. The coupler latch mechanism is controlled by an air cylinder on the SLII's and III's and an electrical solenoid on the SLIV's and can also be manually activated using a special wrench. Electrical connection is via an electrical head located below the mechanical portion of the coupler. It is protected by a swinging door when not in use which automatically swings down when the cars are coupled so that the connections can mate. The electrical head is on a slide mechanism which allows it to be retracted in the event that a car needs to be electrically isolated without uncoupling it.

[train2]

Knew there had to be some type of notch. From my perch in the engine that was not visible. Since the track was active I could not investigate like I would have normally.

[scotty269]

Two Silverliner V's coupling: https://www.youtube.com/watch?v=yIQa_GNgAKs" onclick="window.open(this.href);return false;

For comparison:

Here's a coupling of SPAX 70 with a WCRR baggage car: https://www.youtube.com/watch?v=u5nTkVnb-OI" onclick="window.open(this.href);return false;
Again, from a different angle: https://www.youtube.com/watch?v=57ZF8MF_kzQ" onclick="window.open(this.href);return false;
WCRR 4230 coupling with a WCRR baggage car: https://www.youtube.com/watch?v=XterMc3UADM" onclick="window.open(this.href);return false;

[dowlingm]

This incident report in relation to a Scharfenberg coupler gone wrong may be of interest to posters above:
http://www.raiu.ie/download/pdf/2014r00 ... _doors.pdf" onclick="window.open(this.href);return false;

[train2]

Really my question was more about the coupling and uncoupling of the this type of coupler. In a few photos I have seen on line i can tell there is a notch so that is how it locks into place.

Follow up question is there a manual cut or release lever on these are it electrical or something within the car area. Again I did not notice anything that resembled a traditional cut lever. With the exception of on the new cars in the video linked it looks like there could be a handle in the area of the step below where the sign reads do not ride.

[glennk419]

Really my question was more about the coupling and uncoupling of the this type of coupler. In a few photos I have seen on line i can tell there is a notch so that is how it locks into place.

Follow up question is there a manual cut or release lever on these are it electrical or something within the car area. Again I did not notice anything that resembled a traditional cut lever. With the exception of on the new cars in the video linked it looks like there could be a handle in the area of the step below where the sign reads do not ride.

The current cars use an electrically actuated latch which is operated by a uncoupling key. The older Silverliners had a pneumatically operated latch with small cut levers at the corners of the car as well as one inside of the cab. Both designs could also be manually actuated with a wrench in the event of electrical or air failure.

[ex Budd man]

The SL-IVs use air valves to uncouple (Barksdale valves), the SL-Vs have magnet valves to activate the air cylinder/lock block. Main reservior air is piped to the U/C cylinders on both couplers through small ports on the B/P (lower) poppet. T

Pictures from roberts shop 014.jpg

he electric head has a plastic door over the contacts.

[glennk419]

The SL-IVs use air valves to uncouple (Barksdale valves), the SL-Vs have magnet valves to activate the air cylinder/lock block. Main reservior air is piped to the U/C cylinders on both couplers through small ports on the B/P (lower) poppet. T

Pictures from roberts shop 014.jpg

he electric head has a plastic door over the contacts.

Do I get partial credit on the exam?

That picture appears to be from a (retired?) SLII-III, the dog leash latch on the coupler centering spring is jammed / broken.

[ex Budd man]

The pic is from a IV, I cropped it to fit the format.