I have ridden numerous times in Viewliner roomettes on the Lake Shore, Cardinal, Crescent, and once on the Silver Meteor. My experiences have always been as follows:
There are 2 vents located below each window. Each vent is controlled by a black knob at the end of the vent. You want more air...open the vent. Less air...close the vent. The air coming out of these vents is cool but never cold in my experience.
Located on the wall opposite the sink/toilet are two round vents with a black grated plastic covering. One vent is for the lower bunk...one is for the upper bunk. Both vents have below them buttons to push for "off", "low", "medium" and "high". Again the air temp is about the same as what comes out of vents below the windows.
As for heat, on the wall opposite the sink/toilet, is a round knob to regulate the heat. On the knob are settings for "off", "50", "60", "70","80", etc. But I have found that you ignore the settings. Turn the knob and at around "70" you will hear it click. If you want heat, you move it past the click to the higher numbers...if you don't want heat you turn it the other direction and hear it click to the lower settings ( or just set it at the "off" setting"). The Viewliner roomettes, in my opinion, are more comfortable than the Superliner roomettes. The Superliners have the one vent blowing cool air above the door. Given the age of these cars, some vents work better than others. On warm days if the sun is coming through the windows, the Superliner roomettes can get pretty warm.
Maybe I have been lucky regarding the Viewliners I have been on, but so far they have always been comfortable.
