These were built to accommodate a union agreement to get rid of the old wood cabooses. They were built by the NYC/ Despatch Shops out of 1942-1946 vintage boxcars. there were 189 of them. NYC used Lot Numbers instead of letters to indicate classes. These were NYC Lot 977 built 3-4-66 #18006-18055. The second part of Lot 977 was built in May of 1966 and was numbered 18056-18105

Lot 121 included car 18106-18155 built March 8, 1967 with the second part of lot 121 being built May 11, 1967 cars 18156- 18194

Lot 103 was built by NYC in 1968. There were 160 of them, numbered 18195-18354. Construction overlapped the NYC/PRR merger. The PC Lot number was 152. Both lots lacked roof walks, ladders and had a propane installation for heat and metal grating on the landings. Later they were changed to use kerosene for heat. The exchange of 100lb propane tanks must have been very difficult compared to a hose for kerosene. The cabs were re-built with wood decks during the propane to kerosene conversion.

The PC merger had the Lot 977 and Lot 121 Transfer Cabs re-classed to N-6A while the Lot 103/152 was re-classed as N-9A. The cabs were also used on:

• Penn Central
• Conrail
• Detroit Terminal Railroad
• Indiana Harbor Belt
• Pittsburgh & Lake Erie