Make sure and buy tickets before the day you want ...

Make sure and buy tickets before the day you want to go!

Abbreviated review version:

Wasn't sure how much we would enjoy it - went anyway.
Took the morning trip-less crowded.
ENJOYED IT!! Was cool seeing the view from the top.
Found out it does indeed take minimum of 45-60 minutes to make the round trip that they say it takes.

Full review:

So we were in St Louis for a wedding and had some time to kill before we left for home. Debated on going to the top of the Arch...... Wasn't overly excited about it but decided to go. Took the 10:10 tour on Sunday. Glad we went. It was much cooler than expected. Have a nice museum to wander through while waiting for your tour time. Sunday at 10:10 was not crowded. They advise allowing 45-60 minutes for your trip to the top. We were silly enough to think it would not take that long as we wouldn't spend that much time at the top. (And we went early so we figured it would not be crowded) Well, we didn't spend that much time at the top.

However, your aren't admitted until your time slot. (thankfully, security lines were empty in the morning). We waited for our time slot, (10:10) were admitted to the line and zipped through security. We had to wait for the tram to finish coming down from the top and 1 load of passengers to get loaded and taken to the top and come back down before we got to go. It was 10:25 by that time. 4 minute ride to the top, unload and walk up the final steps to the viewing area. (10:32 now). Spent 12 minutes looking out both sides of the Arch, taking some photos of the view and some selfies of us in the Arch. (10:44 now). Depending on how crowded it is at the top, you may have to wait for a window to open up. We did not. Our tour was only half full and the top was not that crowded (again-go early)

Luckily, didn't have to wait in line to go down, just had to wait for the tram to get back to the top in to go down, took the three minutes ride down and viola , trip complete at 10:54! ( It is a 3 minute trip down-unload/reload-4 minutes back up /unload. Easily 10 minutes so depending on when the tram left before you got in line, and if there are people waiting in front of you, will change how fast you get down)

Complete trip took 44 minutes and the security line was empty for us. When we got back down the security queues were filling up, so it would probably take an hour for the round trip.
That doesn't include times to view the museum or the surrounding area.

So yes, easily an 45-60+ minutes to take the round trip to the top. And that does not include seeing the musuem or the surrounding Park.

Also, they put 5 people in a tram car. You WILL be sitting in close contact with your fellow passingers. Not for claustrophobic people. Very small cars.

AND THE MOST IMPORTANT PART--
don't forget to buy your tickets before the day you want to go. They can and will sell out, especially for the afternoon times.