I beg to differ, mrtruman. The 737-900 absolutely has the legs for EWR-LAS, it's the return that becomes problematic with the hot-and-high nature of LAS. When CO has operated the 737-900 between Newark and Las Vegas, it would usually be scheduled late in the day when temperatures are lower.

EWR-LAS is only 1935nm, so it falls within the 737-900's envelope, but could certainly be weight-restricted when conditions require. With 30 -900ERs now in the fleet, I agree with you, there is no need for CO to schedule the less-capable baseline -900 models on longer hauls. However, it is technically possible, and has happened on numerous occasions.

I'll take the time to look at the 737-900 performance data when I can, but my internet is being painfully slow at the moment, and a download of that size would probably take me over an hour.