Until its last decade in service, the CENTURY boarded passengers (westbound) at New York/Grand Central Terminal and Croton-Harmon; passengers de-trained at Englewood or Chicago/LaSalle Street Station. Eastbound, the reverse was true. The train stopped for servicing and crew changes at Albany, Syracuse, Buffalo, Erie (sometimes), Cleveland (on the lakefront, not at CUT), Toledo and Elkhart (sometimes). After combining with the Commodore Vanderbilt (in 1958), in addition to the above, passengers could board (westbound) at Albany & Syracuse, and detrain at Toledo, Elkhart & South Bend. Eastbound, the reverse was true, except that Syracuse was not a passenger stop. Also, in its early days, there was a section of the train that served Boston via the B&A; I have no information on the stops for that train.
Depending upon what years you are looking at, there were other trains which stopped at the cities you named. #27 New England States lasted as long as the Century and made Rochester and Buffalo.
As far as CUT goes, #25 passed through here at about 4:30AM, while #26 was around 12M. We had better overnight service to New York utilizing #16 Ohio State Limited eastbound and #57 Cleveland Limited and #59 Chicagoan westbound.
After Cleveland Union Terminal opened, the only stop for 25 and 26 (The Twentieth Century Limited) in the Cleveland area was Collinwood, to change engine crews. Sometime well before the 1960's, NYC had started interdivisional passenger train crew assignments, and the train (not engine) crews operated between Toledo and Buffalo.
Up to the end of named passenger trains on the New York Central, 25 and 26 were maintained as the flagships, and their purpose was to serve New York - Chicago passengers with premier service. Even though the entire passenger operation was no longer a profit center, the operation of 25 and 26 as premier service trains contributed more to the balance sheet than if the service quality (and transit times) had degraded. Service degradation would probably have resulted in a greater decline in patronage, becauser local passengers had a different, viable option on 27 and 28.
Trains 27 and 28, the New England States, were the "local" on the same route. Even though they ran between Boston and Chicago, in the 1960's they connected at Albany with New York trains. They also served particular stations like Schenectady, NY and Waterloo, Indiana for the convenience of some large freight shippers; in this case, General Electric.
Let's not forget the CUT mail shuttle that connected with both #25 and #26 at Collinwwod. Mail was swapped during the engine service / crew change.
For a brief period in the mid-60's, #26 was routed through CUT to handle the mail after the shuttle was discontinued. Couldn't match the running time of the Lakefront route, so the move was discontinued fairly quickly.
So how was the Century normally routed around Cleveland?
From the east with a stop at Collinwood, then along the lakefront and LS&MS trackage past West Park yard to Berea?
Was the same routing used eastbound?
The other possible routes could have been via the Big4 past Linndale and Rockport yard, or via the shortline to the south of the city.
Normal routing for the "liners" which did not stop at CUT was via the Lakefront Line.
The Short Line was not often used by passenger trains as it was slower than either the Lakefront or CUT routes.
Another seldom used alternative was Collinwood / Lakefront / Big Four Wye / Old Big Four Main / Clark Ave. / Linndale / BE. For a while in the 1960's, the overnight trains to Cincinnati and St. Louis departed from the Lakefront Mail Hall and occasionally used this route.
Did the Mail Hall Shuttle handle mail by the bag from 25 and 26 at Collinwood? In my short time working there (spring of 1966) 25 and 26 were fueled and handled intact at Collinwood, and both ran via the Lakefront.
I remember the Shuttle working between CUT and the Lakefront Mail Hall. They also came out to Collinwood in the afternoon to get the rear end of 23 (Boston-Chicago M&E) that he cut off while fueling. IIRC, 23 had two rider cars from either Boston or Albany, and the Buffalo-Toledo train crew walked ahead to the mid-train rider to make the cut behind. They left town with the head end, and the Shuttle took the rear end to the Mail Hall.
I rode 23 one day in February 1966 from Albany to Toledo, after working at Dewitt for about 10 days on the blizzard of '66, and I'm sure I remember changing rider cars at Collinwood. In those days, if you wanted a FAST day train to Toledo, and you had a pass, 23 was the way to go if you didn't mind somewhat less-than-stellar accommodations. He often had five units (E-7's and -8's) and he made track speed with few stops.
The "Century" Shuttle handled bag mail which was swapped with the RPO's on #25 & #26 during the servicing stop. IIRC, postal employees actually handled the mail bags.
You're right about #3 and #23 being darn good rides. On one timetable, they were schedulled out of Buffalo a few minutes apart and literally chased each other all the way to Chicago. At one time (no afternoon shuttle) #23 went via CUT and #3 via the Lakefront to work. Then it was a race to see who got to BE first!
We also had the accident one winter at CP-161 when the Dispatcher had told one to slow down to let the other run around. The lead engineer (running west on Tk. #2) called over the radio to his counterpart to dump the air because he couldn't see the headlight on the approaching train! A van had swung loose on the table and was fouling Tk.#1. The other train hit it. The postal inspectors had to tramp through the snow to recover the mail which had been ejected.
We also had an occasion when I was working at Fairlaine when the Vermillion PD called to say that the mail train had just gone through town, but in 2 pieces. The rider coach had separated from the train, and a crew member was holding a fusee out the vestibule. Fortunately, all of the crossings had automatic warning, so they didn't hit any vehicles. We called the Dispatcher, and he told the head end to stop the train which they did at CP-240, the B&O Xg in Sandusky. Apparently, when the train worked at E. 26th St., nobody connected the air line when the rider was recoupled to the train. Both angle cocks remained shut, so the air did not dump when the rider separated! So much for a proper brake test. IIRC, the Conductor was driven to the head end and continued the run; the RE Brakeman (one of the most senioor on his roster) retired on the spot.