Originally, those 2-1 cars were not limited to the Metroliner. They also provided similar up-charge service on some of the regular corridor trains - what are now called Regionals. It was a carry-over of the parlor car service of PRR and other railroads. The service on both the regular corridor trains and the Metroliner was called "Club Service" and included a hot meal. As the Acela was being prepared for launch, the Metroliner Club Service was renamed First Class.
A further perusal of records shows that for a brief period when the
Acelas were going through their first hiccup (was it the brake disc failures or the yaw damper bracket failures I forget) some Metroliners were reintroduced, 5 of the
Metroclubs were re-converted to full length 2-1 seating for use in those
Metroliners. What are today called Amfleet I BC cars were essentially what were Coach cars in
Metroliners.
These full length 2-1 seating
Metroclub or
First Class or whatever they were called (I don't remember) were converted back to half length 2-1 cars almost immediately after the
Acelas came back and the
Metroliners were withdrawn. So there is a chance that the OP came across one of those cars during the brief period that they existed.
On
Metroliners I believe they were called
Metroclub, a name carried over from the original EMU
Metroliners.
My last memory of riding
Club on other than
Metroliners back in the days, was on a set of trains called
New England Express that ran between New York and Boston for a period with a less than 10 min engine change stop at New Haven as I recall.
)
