Missouri Historical Society-St. Louis
My love for amusement Parks and roller coasters began at this park. My first memory was being in someones' arms and they were looking at the coaster, (Thunderbolt) saying "It doesn't look very big." I later found out while doing research, that the ride wasn't known for thrills, but being known as a cause of a lot of bad St. Louis headaches. At some point, my father and I drove by and the park had burned. During the on going trips passing by the old park, less and less of the coaster would be remaining. My last memory was the turn of the coaster nearest the road and a few bottom parts of the hills were all that was left, as well as a few buildings towards the back of the park.  Located near the junction of Natural Bridge and old Rock Road, Westlake Park was a smaller park compared to The Highlands, but it did have a roller coaster. As you can see in the above pictures, Westlake also had a Tumble Bug, the Circle swings with Bi-Planes vs the larger silver jets, a carousel, Custer cars, a swimming pool and of course, a fun house.
These two above photos shows the entire northwest side of the park. The pool is on the right side photo with a bit of the Carousel in the corner. Westlake had two pools, when one was being cleaned, the other would still being used. The photo on the above left shows the parks' "Ideal Skating Rink," bowling and a bit of the fun house roof at the bottom of the photo. This area had very little damage after the fire and was kept open a year or two after the rest of the park was destroyed.
This crime scene picture above, shows the results of one unfortunate unsafe rider, or at least his final path. All amusement parks have to put up with this kind of behavior, driving up the insurance rates, and in some cases causing the close and destruction of a favorite ride. 
This shows the Westlake Thunderbolt just after completion in 1921. The Chain of Rocks Comet would be built a few years later. The Thunderbolt ride was built and designed by John Miller who also designed under wheels for coasters enabling higher and steeper hills, as now the cars would be locked on to the tracks.
Fire was the cause of many parks closure through the years. The building codes were more relaxed and many of the parks would construct buildings that were connected to each other, right next or under their coasters. Westlake had several fires throughout its history.The final one was May 5th, 1955. This fire destroyed most of the coasters' lift hill shown here and several sections throughout the rides' course. Many of the rides next to the Thunderbolt were damaged or destroyed including the parks' Tumble Bug. The sign on the walkway in the background advertises the Tunnel of Love, Fun House, Penny Land and the Ideal Roller Rink. Those attractions were not damaged and would reopen for the next year.  photo: St. Louis Fire Dept. archives, Thanks Dave!
The mist or smoke diffuses the stark fire damage in this photo. What was once food stands is now bits of twisted metal sheeting. Soon all traces of this small park would be gone.
photo: St. Louis Fire Dept. archives, Thanks Dave!
It's easy to see the damage to the Thunderbolts' structure in this photo. Although a good bit of the coaster was still standing, it wasn't enough to rebuild. The three firemen seem to be transfixed at the damage around them as they finally get the fire under control, but to late... ---
photo: St. Louis Fire Dept. archives, Thanks Dave!
This photo looks like it could've been cut from a "Dawn of the Dead" movie. People wandering about, not knowing what to do or where to go. The ferris wheel also survived the fire as did several game and souvenir stands.
photo: St. Louis Fire Dept. archives, Thanks Dave!
This amazing, yet poignant panaramic shot of the back end of Westlake shows the devastation is spread around to the backside of the parks' swimming pool (halfway up, right side). Also, on the left side of the photo, you can see how the first third of the coasters' lift hill has been destroyed. Mid photo is the remaining structure of the Tumble Bug, (the curving small hill). To me, an amazing photo.
photo: St. Louis Fire Dept. archives, Thanks Dave!