In the early 1970s, both Rockets operated with coaches ("chair cars" in the timetable), a diner and a parlor-lounge.
The parlor car service on the Quad City Rocket (#5/6) was provided by Butterworth Tours, using the dome-obs BIG BEN, while RI provided the parlor car on #11/#12.
My folks took my sister and I from LaSalle-Peru to Chicago and return on the Peoria Rocket in July 1972 to visit the Museum Of Science And Industry. I used some of the money I earned mowing the neighbor's lawn to "splurge" for parlor car seats for us. The seat charge was $1.00 per person, each way (still have the ticket stub!).
The RI parlor cars at the time were former Golden State obs-lounges GOLEN DIVAN and GOLDEN VISTA, rebuilt and sqaured off for midtrain service.
Later on (1973?), Butterworth brought in some of his other cars (the BONNIE B and ex-PRR obs THE REVELER) and his cars took over the first class service on the Peoria Rocket as well.
In 1975, when neither Butterworth Tours nor the Rock Island could pay their bills, the cars stopped running and that was that.
The diners ran a bit longer, again because the cooks and waiters were protected by contract and got paid whether the diners ran or not. This was also the reasoning behind TRACK ONE, the stationary diner restaurant in LaSalle Street Station.
The last two diners in service were 411 and 428, both ex-Golden State cars. They were externally virtually identical and had only slightly different interior layouts. Originally, 411 was a "Coffee Shop-Lounge" catering to coach passengers on the Golden State, while 428 was a full diner.
Eventually the diners were withdrawn from service due to the mechanical condition of the cars. 428 (the regular Peoria Rocket diner) developed a cracked center sill in late 1975 and was retired. The 411 continued on the Quad City Rocket until February 15, 1976.
That night, three friends and myself convinced our parents of the gravity of the situation, it being a school night not withstanding (we were all in high school). We got my dad to take us over to Ottawa and my friend Ed talked his dad into picking us up at Geneseo and the four of us boarded #5 and ate the last four dinners ever served on a Rock Island dining car.
Even then, there were still a couple of dining car employees that were protected on the payroll, so they set up shop in one end of one coach on each train, selling sandwiches, snacks and drinks. They put a board up over the backs of a couple of seats, threw a tablecloth over it and arranged their wares. A cooler full of ice on the floor was the refrigeration, and the coffee pot was as often as not plugged into a shaver outlet around the corner in the washroom.
And that was how things remained pretty much through to the end of passenger service on December 31, 1978.
Fortunately, S. Soho & Co. decided to import HO scale brass models of the appropriate Golden State cars (and an Chessie dome-obs for BIG BEN) some years back and I have managed to acquire enough of those to permit me to wallow in my own nostaligia in my basement
Thanks for letting me ramble,