Questions regarding LIRR M-series MU cars

Guys: I have a couple of LIRR MU car questions: On the M1/3 cars on the flanks down below(I think that what they are called) near the B ends there is a date stenciled on some cars: 10/90;9/89;3/91 or a date in the late 80s or early 90s. What did these dates mean? On the M7 cars on the car sides are reinforced panels in the car center as well as on the ends - I call them sideswipe or stabilizer panels am I right? Interestingly,The MNCR M7 does NOT have them. The M7s have many variations between the LIRR and MNCR versions - differences notable for what is basically the same car. Why so MANY differences? MACTRAXX

Those dates stenciled on the "B" ends are when a Life Cycle Maintenance was done. (It may not necessarily be the last one done, but probably was.) Certain components, such as M/A, battery set, propulsion contactors and cam operated switches, and other items, would be replaced.
It was every four years when I was in the apprenticeship. That became every six years. Then no program at all due to budgeting. Wait till it fails, then change it.

Those are rub strips on the sides of the LIRR M-7 cars.
LIRR and MNRR do have at least several minor variations in their M-7/M-7a.

Tom: Thanks again! MACTRAXX

Does anyone know what happend to 7279
& 7118 those two cars seam to be missing.

A few of the M7's have already been mismatched. Not sure of the exact numbers though.

mjb777:

I actually had # 7279 and 7118 in my consist today on train 1734 and 4715 back to Penn. 7118 was the head car going east. I was looking at the screen and noticed it half way through the trip that the numbers were way off the normal sequence. I even asked my engineer and he didn't realize it untill I pointed it out to him. What's the story behind this? Usually, with the M-1/ M-3's it was because the other married car was recked or damaged beyond repair. Did we already lose an M-7?? Still was very strange seeing a married pair with out of sequence numbers.

thats intristing,

I seen a while back, 7171/7280 mismatch and thats becaus the contact in hempstead leaving 7172/7279OOS

so thats 2 pairs now with 7279 and 7118
there still are other mismatched pairs out there atleast 1 or 2

Long Island 7285:

That was the first time I saw this, although if I wasn't paying too much attention, i would of missed it. I haven't seen the other mis-matched pair out there, but i will keep an eye out for it. Where is 7172 and 7279? Are they still OOS?

It was mentioned in a thread a while ago.

http://64.78.30.219/forums/viewtopic.php?t=10857

The 4 cars are still the only mismatched LIRR M-7s.
All cars are supposed to be returned to their respective mates sometime after repairs are finished.

Tom