2. Ballast

60 mm gauge stone ballast is used for all type of sleepers including Points & Crossings in Dhaka Metro.

• True

• False

Ballast is the select crushed granular material placed as the top layer of the super structure in which the sleepers are embedded.

• True

• False

Functions of Ballast

• Provides Resiliency

• Absorbs energy & large voids

• Reduces formation pressure

• All the above

The Ballast provided in between the sleepers is called as __________.

• Shoulder Ballast

• Cushion Ballast

• Crib Ballast

• All the above

The ballast provided at the either ends of sleeper is called as Cushion Ballast.

• True

• False

Ballast zones in the track

• Crib ballast

• Shoulder ballast

• Cushion Ballast

• All the above

Deciding factors for Minimum Depth of Ballast Cushion

• Axle load

• Speed

• Type and Spacing of Sleepers

• All the above

Minimum depth of Ballast Cushion for Test Tracks in Dhaka Metro is _______mm.

• 150

• 200

• 250

• 300

Minimum depth of Ballast Cushion for Depot Tracks in Dhaka Metro is 300 mm.

• True

• False

Requirements of Good Ballast

• Tough & Wear Resistant

• Generally Cubical having Sharp edges

• Cheap & Economical

• All the above