Here are the Speed Limits for the Southwest Chief from Chicago to Los Angeles directly from appropriate Timetables by Subdivsions.
Mendota Subdivision
1. Speed Regulations
1(A). Speed-Maximum
Passenger Freight
Montgomery to Galesburg
....... 79 MPH. ....... 60 MPH.
Chillicothe Sub
1(A). Speed- Maximum
Passenger ---- Freight
MP 185.0 to Ft. Madison,including trains 100 TOB and over
....... 79 MPH. ....... 55 MPH.
Marceline Subdivision
1(A). Speed-Maximum
Passenger Freight
Ft. Madison to W.B. Jct., including trains 100 TOB and over
..... 90 MPH. ...... 55 MPH.*
W.B. Jct. to C.A. Jct. (Main 1), including trains 100 TOB and over
..... 79 MPH. ...... 55 MPH.*
C.A. Jct. to Hardin (Main 2), including trains 100 TOB and over
..... 79 MPH. ...... 55 MPH.*
C.A. Jct. to Bridge MP 425.0, including trains 100 TOB and over
..... 90 MPH. ...... 55 MPH.*
Bridge 425.0 to MP 444.2, including trains 100 TOB and over
..... 79 MPH. ...... 55 MPH.*
* Unless otherwise restricted , the maximum speed for freight trains is 70 MPH.
Topeka Subdivision
1. Speed Regulations
1(A). Speed-Maximum
Passenger Freight
Holliday to N.R. Jct., including trains
100 TOB and over
...... 79 MPH. ....... 55 MPH.
LaJunta Subdivision
1. Speed Regulations
1(A). Speed-Maximum
Passenger Freight
MP124.7 to MP 220.5
...... 79 MPH..........55 MPH.*
MP 220.5 to MP 554.9
...... 90 MPH. ...... 55 MPH.*
Raton Subdivision
1. Speed Regulations
1(A). Speed-Maximum
Passenger Freight
La Junta to Trinidad
..... 90 MPH. ....... 55 MPH.
Trinidad to Raton
..... 79 MPH. ....... 55 MPH.
Raton to Las Vegas
..... 79 MPH. ....... 55 MPH.
Glorietta Subdivision
1. Speed Regulations
1(A). Speed-Maximum
Passenger Freight
Las Vegas to Lamy
... 79 MPH. ....... 55 MPH.
Lamy to Dalies
... 79 MPH. ....... 55 MPH.
Gallup Subdivision
1. Speed Regulations
1(A). Speed- Maximum
Passenger Freight
Belen Jct. to Dalies, including 100 TOB and over
... 55 MPH*.
Main 2
Dalies to Marmon, including 100 TOB and over
... 90 MPH. ...... 55 MPH*.
Marmon to Gonzales, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH*.
Gonzales to Gallup (westward only), including trains 100 TOB and over
... 90 MPH. ...... 55 MPH*.
Gallup to Gonzales (eastward only), including trains 100 TOB and over
... 79 MPH. ...... 55 MPH*.
Gallup to East Winslow, including trains 100 TOB and over
... 90 MPH. ...... 55 MPH*.
Main 1
East Winslow to Gallup, including trains 100 TOB and over
... 90 MPH. ...... 55 MPH*.
Gallup to Gonzales, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH*.
Gonzales to MP 85.9 (eastward only), including trains 100 TOB and over
... 90 MPH. ...... 55 MPH*.
Gonzales to MP 85.9 (westward only), including trains 100 TOB and over
... 79 MPH. ...... 55 MPH*.
MP 85.9 to Marmon, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH*.
Marmon to Dalies, including trains 100 TOB and over
... 90 MPH. ...... 55 MPH*.
Seligman Subdivision
1. Speed Regulations
1(A). Speed-Maximum
Passenger Freight
Westward Movements Both Tracks East Winslow to Maine, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH.*
Eastward Movements Both Tracks Maine to East Darling, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH.*
East Darling to East Winslow, including trains 100 TOB and over
... 90 MPH. ...... 55 MPH.*
Both Tracks Both Directions
Maine to East Crookton, including trains 100 TOB and over
... 90 MPH. ...... 55 MPH.*
East Crookton to West Seligman, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH.*
Main 1
West Seligman to Peach Springs, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH.*
Peach Springs to Needles, including trains 100 TOB and over
... 90 MPH. ...... 55 MPH.*
Main 2
Needles to Getz, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH.*
Getz to MP 484.0, including trains 100 TOB and over
... 90 MPH. ...... 55 MPH.*
MP 484.0 to West Seligman, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH.*
Against the Current of Traffic
MP 446.8 to MP 465.8, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH.*
MP 467.6 to MP 484.0, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH. *
MP 485.8 to MP 509.4, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH.*
MP 511.5 to MP 526.9, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH.*
MP 528.8 to MP 551.7, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH.*
MP 553.5 to East Needles, including trains 100 TOB and over
... 79 MPH. ...... 55 MPH.*
Needles Subdivision
1. Speed Regulations
1(A). Speed—Maximum
Passenger Freight
Main 1
Needles to Goffs, including trains 100 TOB and over
...... 79 MPH. ...... 55 MPH.*
Goffs to Bagdad, including trains 100 TOB and over
...... 90 MPH. ...... 55 MPH.*
Bagdad to Pisgah, including trains 100 TOB and over
...... 79 MPH. ...... 55 MPH.*
Pisgah to Daggett, including trains 100 TOB and over
...... 90 MPH. ...... 55 MPH.*
Daggett to Barstow, including trains 100 TOB and over
...... 79 MPH. ...... 55 MPH.*
Main 2
Barstow to Daggett, including trains 100 TOB and over
...... 79 MPH. ...... 55 MPH.*
Daggett to Pisgah, including trains 100 TOB and over
...... 90 MPH. ...... 55 MPH.*
Pisgah to MP 685.8, including trains 100 TOB and over
...... 79 MPH. ...... 55 MPH.*
MP 685.8 to MP 671.4
...... 79 MPH. ....... 45 MPH.
MP 671.4 to Bagdad, including trains 100 TOB and over
...... 79 MPH. ...... 55 MPH.*
Bagdad to MP 646.1, including trains 100 TOB and over
...... 90 MPH. ...... 55 MPH.*
MP 646.1 to Needles, including trains 100 TOB and over
...... 79 MPH. ...... 55 MPH.*
Cajon Subdivision
1(A). Speed—Maximum
Passenger Freight
Barstow to San Bernardino
...... 79 MPH. ....... 55 MPH
San Bernardino Subdivision
1. Speed Regulations
1(A). Speed—Maximum
Passenger Freight
San Bernardino to Fullerton Jct.
...... 60 MPH. ...... 50 MPH.#
Fullerton Jct. to MP 144.5
...... 79 MPH. ...... 50 MPH.#
San Pedro Jct. to Harbor Jct., Main 1 and 2
...... 40 MPH. ...... 40 MPH.#
San Pedro Jct. to MP 144.0, Main 3 and 4
...... 65 MPH. ...... 40 MPH.#