“Braking” it Down! (Part 1)

 Preface: The brake run is one of the most important components of a roller coaster. In the modern amusement setting, brake runs are crucial to the successful operation of high-capacity roller coasters. This installment of Coaster Chat will serve to explain what brake runs are, the different types of brake runs, and how each of them works to keep the roller coasters up and running.

Coaster Chat 2: “Braking” it Down! (Part 1)

Introduction

What is a brake run? A brake run is a fundamental element of roller coasters. It is what allows the coaster train to be stopped before the station. They also prevent trains from crashing into each other midway through the ride. Brake runs have changed in design as technology and coasters have changed. Originally, on wooden coasters, brake sections were operated manually. This is still found on a handful of classic roller coasters, such as Sea Dragon at Columbus Zoo or Leap The Dips at Lakemont Park (the world’s oldest operating roller coaster). In the modern era, brakes are operated automatically, using sensors to monitor the speed and position of a train, slowing or stopping it accordingly. There are three primary types of brake runs worth discussing: trim brakes, mid-course brake runs, and final brake runs. The latter two are types of “block brakes,” A concept we will also discuss.

Trimming and Blocking

To understand brakes as a whole, it is important to understand what trimming is. On a roller coaster, the act of “trimming” a train means slowing it down to a desired speed. Trim brakes, specifically, are brakes that serve only this purpose. In practical use, trim brakes work by using two sensors in succession to calculate the speed of a train. The brake follows these sensors and applies enough pressure to bring the train to an appropriate speed. Although some people don’t like the loss of speed, trim brakes are an important tool to help roller coasters undergo less wear-and-tear, as well as providing a more comfortable and less intense ride. That being said, rides like Intimidator at Carowinds (Charlotte, NC) have so many trim brakes that some coaster enthusiasts have nicknamed it “In-trim-idator,” a rather fitting jab at the design.

Trim brake on Raging Bull at Six Flags Great America (Gurnee, IL) (VF15, themeparkreview.com)

Before we cover mid-course and final brake runs, we will briefly talk about block zones, or “blocks.” When a roller coaster runs more than one train, it is important to divide the track into blocks. A block is an individual area of track that can only be occupied by one train at a time. Each block is separated by a block device. Block brakes include mid-course and final brake runs, but lift hills also have the capability of preventing a train from progressing. Blocks allow more than one train to travel along the track by providing a method to stop each train at the end of any given block zone. If for any reason, a train enters a block brake and the following section of the track is not clear, the block brake will stop the train until the train ahead has finished clearing the section. This occurrence is known as a “cascade.” In most cases, cascades are uncommon, as the Standard Operating Procedures used by operators take into account how early a train can be dispatched to prevent them from happening. Some other common reasons that block brakes might stop a train include “valleying” (when a train fails to maintain the required speed to clear the layout and gets stuck), “ghost trains” (when the ride’s computer detects the presence of a train that is not actually there, leading to a fault*), and power outages. Block brakes play a crucial role when it comes to safe roller coaster operations.

A “block map” of a sample roller coaster, in which each color represents a different block zone (John German)

Mid Course and Final Brake Runs

Now that you have learned about trimming and blocking, we can combine these two concepts to talk about mid-course brake runs (MCBRs) and final brake runs. As the name implies, MCBRs are found in the middle of a roller coaster’s layout and final brake runs, at the finale.

Roller coasters can feature any number of MCBRs, but the most common ratio is one MCBR for three trains operating (this leaves a final brake run and station as the other two block brakes for the other two trains). MCBRs serve as block brakes, but may also serve as trim brakes. To an untrained rider, MCBRs are the most noticeable form of trim brake, as roller coasters often undergo a large deceleration when traveling across them. The speed they bring you to varies, but it is typically easy to tell if you are being slowed down on one. Rides like Goliath at Six Flags Magic Mountain (Valencia, CA) slow riders to a near-stop on their MCBRs, whereas rides like Steel Vengeance at Cedar Point (Sandusky, OH) often have minimal to no trimming at all. It should be noted that although MCBRs can be used as trim brakes, they are not the same as stand-alone trim brakes. However, using MCBRs as trim brakes may eliminate the need for trim brakes later in the layout.

Gatekeeper at Cedar Point (Sandusky, OH) corkscrewing over its MCBR (Incrediblecoasters.com)

Final brake runs may also serve to trim a train, however, the purpose of trimming on a final brake run more or less brings a train to a reasonable speed for the holding/station brakes to stop it. On most coasters, the final brake run, any holding brakes, and station are integrated onto one straight section of the track. In general, the final brake run is generalized as this straight section (minus the station) but may include enough block zones to hold the remaining trains that are not in the station. This is also a type of cascade but is referred to as “stacking” in this scenario. Stacking generally occurs when operators are not dispatching trains quickly enough, and lowers hourly capacity if left unresolved. Solutions for stacking include increasing the speed of operations (through practice) or putting one or more trains into storage.

A train enters Scorpion’s final brake run at Busch Gardens (Tampa, FL)

Fail-Safe Brakes

If you ever worry about the power going out on a coaster and the trim/block brakes not working, this is the purpose of fail-safe brakes. All brakes that are operated electronically will automatically close in their unpowered position. This will ensure that the train comes to a stop and doesn’t crash. From there, riders can be evacuated from the ride. In some cases, trim brakes may be used (sometimes exclusively) to slow down a train during a power outage. In this case, they can force the train to valley without rocking back and forth for too long, allowing for the evacuation process to begin sooner. 

Conclusion

Next time you are at an amusement park, watch the roller coasters carefully. With a little practice, you can easily identify the different brakes on a roller coaster, point out block zones, and maybe even see how trimming is being utilized. Now that you know the functions of brakes, lookout for a future post when we discuss how brakes have evolved mechanically, and the different types of brake devices.

Ride-On,

John

*Broadly, a fault is any occurrence in which a ride’s computer malfunctions, leading to the ride being stopped automatically as a safety precaution.