Locomotive and Car Brake Systems Unit 5 Locomotive and Car Brake Systems

Objectives Describe the different train brake systems. List the different types of brake shoes. Describe how to identify common brake problems. Demonstrate a working knowledge of potential indicators, physical evidence and investigative techniques unique to brake system related fires. The objectives of this unit are: Describe the different train brake systems. List the different types of brake shoes. Describe how to identify common brake problems. Demonstrate a working knowledge of potential indicators, physical evidence and investigative techniques unique to brake system related fires.

Identification of train brake systems Air brakes Locomotive Railcar Hand brake Wheel Ratchet style Dynamic brake (electric) We will looking at the different train braking systems. These include: Air brakes Locomotive Railcar Hand brake Wheel Ratchet style Dynamic brake (electric)

Locomotive Air Brakes Cylinder rod extended Brake cylinder Brake shoe Here is a locomotive wheel truck which consists of the wheels, brake system and suspension. Located on the wheel truck you will note the brake cylinder rod and brake shoe. Note that the brake cylinder on the left above the wheel truck is in the applied position, the brake cylinder ram is exposed (shinny metal) and the brake shoes are applied against the wheels.

Locomotive hand brake Here is a wheel type hand brake. This hand brake must be applied anytime personnel operating the locomotive leave the locomotive. If the chain indicated by the yellow arrow is tight, the brake is on. It is noteworthy that if this type of brake if left on during movement, the engineer and conductor would smell it after it heats up. Note blue flag signal protection.

Ratchet style handbrake on locomotive This is the lever style handbrake found on some locomotives. The SD 40-2 which is printed on the frame of the locomotive signifies the model number and type of locomotive. Check the record or log on the locomotive to see if the brake was set by the train crew. This record is included with the train orders located in the locomotive.

Car hand brake This is a wheel type handbrake on a rail tank car. Note the chain below the wheel, which is attached to an assembly under the car frame that sets and releases the hand brake on the car. There are certain standards when this handbrake must be applied, for example, when a car is left behind or at a siding. If a number of cars are left behind or at a siding, the handbrakes must be set on a certain number of cars, not just set on one car.

Dynamic brake grids Dynamic braking is used to slow trains, particularly on descending grades. The locomotive traction motors act like generators which slow the wheels by inertia. The electrical current generated from retarding the train is fed to resistance grids where it is then dissipated as heat. You could think of these grids as a giant toaster. Large fans on top of the locomotive pull cooling air over the grids. The blue arrow shows the dynamic brake grids. Maximum dynamic brake effect takes place between 19 and 25 miles per hour, although they are effective down to approximately nine miles per hour. When used in conjunction with the air brakes of the train, the dynamic brake system will reduce the wear and tear on the brake shoes and lessen the chance of fire starts. Dynamic brakes will only slow a train, they cannot stop it.

Throttle Train brake Dynamic brake Independent brake Here is a view inside a locomotive cab. When the train brake is applied, it stops or slows the entire train. The independent brake would control the locomotive or cars only. The dynamic brake slows the locomotive only through electrical current only. The throttle controls the power of the locomotive. In theory, the engineer can apply a variety of different braking applications, independently, or a combination at the same time depending upon conditions. Independent brake

Brake styles Clasp type 2 brake shoes per wheel Single shoe type Here are the two commonly encountered brake styles. The clasp style brake consists of two shoes per wheel which is shown in the upper photo. The lower photo depicts the single she type which has only one shoe per wheel. Single shoe type 1 brake shoe per wheel

Types of brake shoes Metal brake shoes The metal brake shoes which are shown on the left are being phased out and replaced by composition material brake shoes on the right. The metal backing plate on the composition shoe attaches the shoe to the brake arm assembly. Unless the metal backing plate has made contact with the wheel, there is very little chance that the composition brake shoe would cause a fire. Metal brake shoes have a much better chance of starting a fire due to the metal upon metal contact when the brake is applied. Composition brake shoes will be found on both locomotive and rail cars. Composition brake shoe (non-metallic)

Rail car brake shoe type and size The stencil indicates that these railcars have a 1 ½ inch, high friction composition brake shoe on the left car and a 2 inch, high friction composition brake shoe on the right car.

Disc brake shoe This type of brake is not found on locomotives or freight cars. It is used on AMTRAK passenger cars and on high speed light rail passenger trains. It may also be found on the business cars of freight railroads. A problem that has been encountered by some railroads is the disk brake locks up the wheel and causes it to drag, thereby creating a flat spot on the bottom. This could result in fires being started by hot pieces of wheel or track being thrown off into the fuel bed. The system is not unlike the brakes on a car of light truck.

Common brake problems The following section are some common brake problems you may observe during your investigation.

This photo shows how composition brake shoes can wear.

Worn composition brake shoe The upper portion of this composition brake shoe is worn. Without replacement and with continued brake applications, the composition material will be worn away. This will increase the chances of metal on metal contact with the wheel.

Composition brake shoe worn through to backing plate The composition brake shoe has been worn away which resulted in metal to metal contact between the wheel and brake shoe metal backing plate. The wear marks on the wheel are a result of the backing plate in contact with the wheel.

Other miscellaneous wheel issues The following slides will address some other miscellaneous wheel issues.

“Treading” metal material built up on wheel Wheel flange This metal build up referred to as treading, is shown on this wheel. It is the result of a brake shoe hang up which can cause the car to derail. With the tread buildup, the wheel flange, which is the inside edge of the wheel, is no longer tall enough to hold the car on the rail.

Wheel flange lubricator This device is being used on some railroads. As you are inspecting the train, you may see this on a locomotive. The purpose of this device is to apply a lubricant to the wheel flange to reduce wheel wear when the unit goes through a curve portion of the railroad tracks. The lubricant is molded into a stick form which is generally good for about 30 days. The lubricant stick is held in place by a spring tension device located within the rectangular tube like assembly. This is a metal device that may fail and come in contact with the rail wheel.

Wheel slip Wheel slip can be caused by excessive acceleration, or when a substance such as sand, oil, or ice has built up on the top of the railroad track. This results in not only deterioration of the track, but also metal can be cast off. If the metal material is hot enough and the receptive fuel bed is dry enough, ignition can occur. Investigators should note the condition of the track adjacent to the fire origin area. The blue pen in the foreground is pointing to a metal fragment that is a result of wheel slip.

Wheel bearing assembly The arrow points to a wheel bearing assembly, the lower photo show a “bad order” axle that was pulled out of service. When a wheel bearing becomes overheated, there will be notification to the train crew and the dispatcher when this wheel passes a hot box detector. The axles of the train are numbered from the first locomotive axle to the last car axle. The notification to the train crew would alert them to which axle activated the hot box detector. The train crew will stop the train and do a physical inspection of not only the axle in question, but a number of axles before and after the overheated axle.

Hot box, dragging equipment detector Notifies train and dispatcher of problem Hotbox and dragging equipment records: Milepost number Total axle count Suspected axle number Time of notification The hotbox detector is designed to alert the train crew of an overheated axle. The dragging equipment detector alerts the crew to items that are dragging on the train. There is also another detector called a high wide detector, it alerts the crew if a car is to high or wide to pass through a tunnel or overpass. The detector in the photo is a dragging equipment detector. The next slide will have an audio of an actual alert to the train crew and the dispatcher of a dragging equipment situation.

Potential indicators, physical evidence, and investigative techniques In this section we will be looking at potential indicators, physical evidence, and investigative techniques for the fire investigator in reference to locomotive and car brake systems.

Specialized investigative tools Magnet Metal detector Metallurgist report PPE The investigator may need special tools and assistance from other sources. Two magnet which would be helpful are a hand held type and a smaller pencil style. A metal detector would be helpful in locating potential metallic material located in the origin areas of the fire. A metallurgist report maybe needed to confirm the type, likeness of the suspect metal. Lastly, don’t forget your PPE!

Here is ferrous metal picked up by a larger hand held magnet Here is ferrous metal picked up by a larger hand held magnet. The white paper wrapped around the magnet makes a good background to observe ferrous material. A smaller pencil style magnet is also useful in retrieving metal that has burrowed deep into the railroad ties or duff.

Specialized Investigative techniques: Items to note during investigation Multiple starts? Origin area distance from track Wheel surface condition Rail surface condition at scene of fire Area topography Uphill or downhill grade Curve area where brakes may be applied Sidings The investigator upon arrival at the fire scene should observe the following. Where is the origin area of the fire in relation to the rail? Are there multiple starts? How far is the origin from the rail ? What is the condition of the wheel and rail surfaces ? Does the topography and track layout include curves, grades, or sidings ?

Sidings Sidings are a piece of track designed to park or pull off a train or cut out a car. They are generally long enough to park an entire train off the main line so another train can pass. Sidings are also used as staging areas when maintenance operations are occurring within a designated block of track. These sidings are generally adjacent to the main line and ghave switches at both ends for the railroad equipment to enter or depart from either direction from the main line.

You may find a single fire or multiple fires over several miles. You may find a single fire or multiple fires over several miles. The failure of a brake or brake shoes may cause ignitions on both sides of the railroad track. Generally, but not always, carbon caused fires are on the downwind side of the tracks. The arrows shows one of multiple starts along the railroad track.

What ignition source caused this fire ? This fire occurred on Willamette National Forest in Oregon in 2002. We will look at what caused this fire in the following slides. One of the investigations caveat’s for the investigator is there is a lot of discarded material along a railroad track. The investigator must determine what is new and what is old and not get excited when a piece of metal is found that may have been lying there for 40 years.

Specific fire cause: Composition brake shoe failure Ferrous metal fragments are indicated by yellow evidence markers. The ferrous metal fragments were found at varying distances from the rail. The red flags were used to show burn indicators.

Specific fire cause: Composition brake shoe failure The ferrous material located near evidence marker four has actually been formed in the curve that would be found on a rail wheel. The lack of oxidation would indicate that this ferrous material has not been subjected to moisture.

Composition brake shoe failure Note worn groove and shine on wheel Wheel surface wear is evidenced by deep grooves cut into the wheel surface. The shiny metal surface on the wheel would indicate that metal to metal contact has been made.

Brake shoe failed because the railcar handbrake was not released prior to train movement The fire investigation concluded that the cause of this wildfire was a result of brake backing plate fragments. The backing plate fragmented due to lack of railcar handbrake release prior to train movement. The resulting tension of the brakeshoes on the moving wheels caused pieces of heated backing plate to dislodge onto the rail bed and right of way, thereby causing dry grass and brush to ignite. The fire burned a total of 160 acres and cost $2.2 million dollars to suppress.

16 feet from outside rail to origin This fire occurred on the Plumas National Forest. Note the distance of 16 feet from the rail to the fire origin area. What may have caused this fire? What fire causes can you rule out ? What possible fire causes must you consider ?

Found at fire origin approximately 16 feet from rail This is the origin area of the fire that occurred on the Plumas National Forest in the previous slide. The lack of rust on the metal would indicate that this material was recently deposited in this fire origin area. Found at fire origin approximately 16 feet from rail

Case study: What ignition source caused this fire ? Origin area What fire causes can you rule out? What fire causes must you consider?

The elimination of other fire causes Motor vehicles and equipment Electrical utility / power lines Children caused fires Smoking Railroad Lightning Debris burning or campfire Incendiary Other possible causes ? It is imperative that the investigator rule out other fire causes at the scene. A number of additional activities may traditionally occur along a railroad right of way.

Specific fire cause was dynamic brake grid failure Specific fire cause was dynamic brake grid failure. Note the melted metal The dynamic brake grids dissipate the heat caused by dynamic braking. In this case, some of the cooling grids failed and caused the fire. Portions of the grid were ejected, landing in a receptive fuel bed, causing the fire.

Dynamic grid failure This is another example of dynamic brake grid failure. The top photo shows the paint in and around the brake grid which has been burned. The right hand side of the lower photo shows the brake grid, which has been blown out. This failure caused a fire.

Summary Air brakes, hand brakes, and dynamic brake grids can fail. Composition brake shoe material can be worn away, leaving the metal backing plate which can come in contact with the rail wheel. When a dynamic brake grid fails, the train crew may hear a loud noise or explosion. Dynamic brake grid fragments may be found both inside, and some distance away from the railroad tracks. Dynamic brake grid material may or may not be magnetic. Air brakes, hand brakes, and dynamic brake grids can fail. Composition brake shoe material can be worn away, leaving the metal backing plate which can come in contact with the rail wheel. When a dynamic brake grid fails, the train crew may hear a loud noise or explosion. Dynamic brake grid fragments may be found both inside, and some distance away from the railroad tracks. Dynamic brake grid material may or may not be magnetic.

Summary When hand brakes are inadvertently engaged on a moving locomotives or rail car, you may see wheel discoloration, grooves worn into the wheel, and fragmented brake shoes. Metal brake shoes, although being phased out, should not be overlooked as a possible fire cause. When hand brakes are inadvertently engaged on a moving locomotives or rail car, you may see wheel discoloration, grooves worn into the wheel, and fragmented brake shoes. Metal brake shoes, although being phased out, should not be overlooked as a possible fire cause.

Test Questions Brake shoe fires may: A. Be found on flat ground B. Be found on steep grades C. Be found on either side of the right-of-way D. All of the above D. All of the above

Test Questions The metal backing plate from a composition brake shoe can cause a fire. A. True B. False A. True

Test Questions .Dragging equipment or hot box detector notifications are typically: Known only by the train crew Known only by the railroad dispatcher Known by both the train crew and the railroad dispatcher C. Known by both the train crew and the railroad dispatcher

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