F-Unit and E-Unit line-up´s

[Anonymous]

What have been the most common F-Unit and E-Unit line-up´s on trains back in the 40ies, 50ies and 60ies?
What was the maximum of F or E Units coupled together?
The longest that I heard of are the following:
On the Santa Fe, sometimes a F-7 A-B-B-B-B-B-B-A Unit line-up was possible in front of passenger trains, and on the Union Pacific, E-9 A-B-B-B-A Unit line-up´s were also common on passenger trains. And then I heard of Chicago Great Western using F-3 / F-7 A-B-B-B-B-A Unit line-up´s in front of it´s freight trains.
Does anybody know more about this?

[PBenham]

For the most part early diesel owners had to limit the number of units in a consist because of an inherent limitation in the available electronic technology that slowed response time of a unit "too far back" in a consist . The usual maximum number of units for Lehigh Valley was five units. Additional units were only permitted under special circumstances. This was also allowed if there were two crews, not uncommon, since most Fs did not have nose M.U. I can testify that New York Central permitted six units, provided at least three of them were GP9s or newer EMDs. Otherwise, mixed builder consists were limited to five units.

[csmith9474]

I have done quite a bit of research in regards to Santa Fe passenger trains, and have seem many pictures of F7 lashups. The longest F7 consist I have come across on Santa Fe passenger trains were in the following orders: ABBBA, ABBBB, AABBA. I am sure that longer lashups were definately possible, but wouldn't have happened often (possibly for power moves). Too many locos can actually impede the performance of the train as a whole. And if I am not mistaken, their F7s could lead F3s, but F3s could not lead F7s (or is that the other way around).

[Anonymous]

It would depend somewhat on the gradients found on the railroad. Back in the late '40s the Reading Company found that ABA sets of F3s and FA1s were the maximum that could be used on the grades on the Catawissa branch. ABBA sets of F3s ,FTs and FA1s were used several times and were found to routinely break the 4" by 6" coupler shanks that were commononly found on interchange cars in those days. On many of the other mains ABBA sets were used without problem by the Reading.