Thomas,
You ask a good question and in reality there several different Pre War couplers on O gauge Tin Plate Lionel trains.
Look at it in this mannner and it becomes a might easier to understand, there are both manual and auto couplers on Pre War Lionel trains. The manual have the swing over locking gate and are all metal they must be manually operated, the auto coupler rolling stock all have a black synthetic over cap, and are designed differently than the manual couplers because they have auto uncoupling capability with the uncoupling track. These 2 different type of couplers were never engineered to be used together, although some people do mix the rolling stock when the cars match up, not all do however. Remember also the Lionel 2600 series Tin Plate rolling stock is smaller than the regualar O guage and although it will match up with the regular Lionel Tin Plate O Gauge, coupler height ajustment has to be made, most all 2600 series rolling stock came with Lionel auto couplers, however I have seen some custom manual couplers at the train shows. So when your are purchasing rolling stock both original and repro
you must identify the rolling stocks coupler type, before purchasing, so it fits with the particular train you already own. All my Tin Plate trains have the auto couplers, however many people love the manuals and only own them, some Tin guys own both.
PCRR/Dave
A Lionel Original 810 Crane car coupled to a 2600 mini Gondola and 2660 Crane Car all
with Lionel Auto Couplers. Disreguard the Erie Car please.
The 263E work Train with auto couplers and a mixture of both original Lionel 2600 and regular Lionel/MTH, O gauge rolling stock.