I had a chance to head out to the Tuscaloosa station today about 1:15. I saw #20 heading East, followed by #19 heading west about a half hour later. It was very cool!
Just looked on Amtrak's web for the new schedule. It shows for Tuscaloosa:
19: 1:11 pm
20: 1:01 pm
Now that would make them meet very close to but north of Tuscaloosa if they are on time.
Just for curiosity I looked at a 1988 NS employee timetable I have, and unless they have built a new siding, this schedule is simply impossible. It would require a siding to be located with the south switch something like 2 to no more than about 3 miles north of the Tuscaloosa station. (You have to consider acceleration, braking, wait for signal to leave the siding and standing time in the station, as the posted time is supposed to be the leaving time.)
According to the ETT, you have
143.0 Birmingham Amtrak Sta. (zero milepost is Chattanooga)
156.0 Burstall - end of two main tracks
164.5 Kimball - 11,835' siding
172.3 Woodstock - 15,214' siding
186.5 Fleming - 9,436' siding
198.4 Tuscaloosa - station
200.0 Tuscaloosa Siding - 10,088' siding
there are six more sidings between here and Meridian, but I am tired of writing.
292.7 Breyer - begin two main tracks
295.0 Meridian Passenger Station
What you saw, about 30 minutes between trains works out just about perfectly for a meet at Fleming.
For your information as a rookie, this piece of railroad, Chattanooga to Meridian is frequently referred to as the AGS for Alabama Great Southern. It kept its corporate existence under the Southern Railway System umbrella until sometime in the 70's or thereabouts. Going south from Meridian, the mileposts start over, and this is the New Orleans and Northeastern, mileposted from the Meridian end. Shortly east of the Birmingham station going eastward, you join the Southern Railroad, which is mileposted from Washington DC. The southern railroad line turned north at that point to go past the former Terminal Station in Birmingham, and then continued west to Columbus, Mississippi. I believe the parts west of Parrish AL are now abandoned.
If you think Atlanta to Birmingham is crooked, you ain't seen crooked until you get west of Birmingham. I had the experience of riding a detour of the Tennessean in the mid 60's that came through Birmingham due to a derailment on the bridge at Decatur. It took 5 hours to go the about 138 miles from Birmingham to Sheffield AL, and only 5 minutes was lost due to a meet. 40 mph was as fast as you got, and much was slower. Our engineer and conductor went dead on the law, but since we had a pilot engineer and conductor, the train kept going anyway. (Parrish to Sheffield is also called the Northern Alabama, and was also a separate company at one time. A piece of it, Haleyville AL to Jasper AL had passenger trains - City of Miami - right up to Amtrak because the Illinois Central had trackage rights over it to reach Birmingham. Jasper on in to B'ham was on the Frisco.)
George