M-1 and M-3 cab windows

[R36 Combine Coach]

I know some M-1s were retrofitted with M-3 cab windows, the horizontal sliding type, replacing the original vertical drop sash. Is it possible vice versa to retrofit a M-3 with a drop sash? If not, what modifications or design changes prevent so?

What was the reason from the change from vertical drop sash to the horizontal type? Was it a MTA or Budd decision?

[BuddR32]

The only M1 I recall with the sliding sash window was 9386, which was involved in some form of collision. The Geritol Gang put it together nicely, but there was damage that wouldnt allow the drop sash window to operate up and down. Hence it was easier to install the sliding sash window.

As for a backwards retrofit, it would most likely be possible, with a LOT of handi-work, I dont believe the M3 carbody structure is far different than the M1, meaning extra structural bracing under the cab window area

As for whose decision it was, I cannot answer. I'd wager it was a Budd decision, as the M3/M3a are the only fleets with them. The M4, M6 had the drop sash window, as does the M7, M8 & C3. The M9 smartly, has the sliding sash window, which was a LI decision.

[MACTRAXX]

R32: I remember the use of the M3-type "D window" on M1 pair 9259-9260 and the mention it
was a test to see if retrofitting more M1 cars would have been worthwhile - and since it was not
repeated it apparently wasn't...

I recall that the M1 car drop-sash window "pocket" was a problem spot for water intrusion into
the car body hence the test of the M3 type outside frame D window. The only apparent trouble
with the D window opening and closing is from icing during the winter in the window track.

Metro-North had an interesting openable window variation that was used on the M2/M4 fleet
which was a three-stage sliding window - the trouble was that the third section was fixed in
place leaving a limited space when the window was used by train crews. Perhaps Dutch or
someone more in the know about MNCR can contribute more information about them - and
what the bulk of the M2/M4/M6 fleet was equipped with...MACTRAXX

[BuddR32]

I forgot about 9259-60! Small number still. I'd like to hear more about the MNR three stage sash.