Re: automobile cars
Rupert & Maureen <gamlenz@...>
In June 1910, the ARA accepted the proposed classification of cars that had been drawn up at its request by the Master Car Builders Association. The complete list was published at the time in various trade journals including Railway Age Gazette 1910 vol. 48, beginning on page 1620. This can be viewed or downloaded at https://babel.hathitrust.org/cgi/pt?id=njp.32101049000712;view=1up;seq=1662
There were four classes for “General Service Freight Equipment Cars” –
XM Box Car
XV Box Car Ventilated
One document I saw (http://www.nakina.net/other/aartype.html) derives its list of AAR Mechanical Designations from Official Railway Equipment Registers starting in 1917. The range of years to which the designations apply also are listed.
Unfortunately, the list does not go back before 1917 so the word "carriage" does not appear in the descriptions. Note that "XA" evolved and overlapped ""XAR" and "XF" appears to have lasted into the mid-1960s.