The May 1955 Official Guide shows the following:
Distance 541.8 miles
The Streamlined Meteor lv StL 7.00 pm ar OkC 8.00 am
Lv OkC 7.00 pm ar StL 7.45 am (other trains on the route not identified as streamlined)
Westbound had 3 sleepers for OkC and 2 setouts at Tulsa (ar 5.00 am, could be occupied until 8.00)
Eastbound had 2 sleepers from OkC and 2 from Tulsa, (lv 9.45 pm, open at 9.00)
The other OkC sleeper came back on another train
Diner Lounge Obs, Chair Lounge Buffet, and Reclining Chair Cars both directions
Also a Fort Smith sleeper both directions and a Joplin sleeper eastbound, on and off at Monett
I didn't note the times at Springfield, but (in case you're thinking in terms of average speeds) there were 7 intermediate regular stops westbound, with dwell times shown at Newburg 5', Springfield 20', Monett 20', Tulsa 30', plus 9 conditional stops.
Eastbound, 5 intermediate regular stops, including Tulsa 20', Monett 15', Springfield 10', Newburg 5', plus 11 conditional stops.
Trivia: There were 3 stations in OkC: ATSF, MKT, and SLSF-CRI&P. Daylight Saving Time was not established nationwide until Spring 1967; until then it was a patchwork of state and local option, and the summer issues of the Guide devoted about 3 pages to a "LIST OF CITIES AND TOWNS OBSERVING "DAYLIGHT SAVING" TIME (note the quotation marks); in May 1955 St. Louis and suburbs were on DST, but the rest of Missouri and all of Oklahoma were on standard. Standard Time was shown in timetables; thus the 7 pm St. Louis departure was actually at 8 pm local time, and the 7.45 am arrival was actually at 8.45 local time. Travelers had a lot to keep track of. Each train shown had a 14-Roomette-4 Double Bedroom sleeper, one of which, CIMARRON RIVER, still exists in private ownership and shows up occasionally in excursion and charter service.