Track Engineering - Ballast & Drainage

What is the typical size of ballast?

• 10mm

• 70mm

• 100mm

• 25mm - 64mm

What are the functions of ballast? (Select more than one)

• Free draining

• Allows the track to be adjusted by manual/mechanical means

• Gives vertical and lateral stability to the track

• To make the track look neat and tidy

What are the properties of ballast? (Select more than one)

• Angular, strong and durable

• Regular in size

• Smooth

• Shiny

• Well consolidated

What is the minimum shoulder width?

• 375mm - 450mm

• 250mm

• 450mm - 600mm

• 1m - 1.5m

What is the minimum shoulder height?

• 250mm

• 300mm

• 1m

• 125mm

Drainage should allow water to disperse away from the railway and prevent flooding...

• True

• False

What is the minimum crossfall in the track substructure?

• 1:5

• 1:500

• 1:20

• 1:100

What is the purpose of a catchpit? (Select more than one)

• To allow inspection and cleaning

• To supply clean water to the environment

• To protect the ballast membrane

• To allow drains to be kept clean and free of debris

What evidence is there of a blocked drain? (Select more than one)

• Catchpit full of ballast

• Dry catchpits

• Flooded catchpits

• Vegetation growing in the four foot

How can we locate blocked drains? (Select more than one)

• Visual inspection

• Cameras

• Throw ballast down the catchpit

• Water dye test