CTB CTB Track Systems & Components 1 — Questions and Answers
Question 1: What is the primary function of a rail joint bar (fishplate) in a track system?
- To connect two rail ends mechanically and maintain vertical and horizontal alignment (Correct answer)
- To anchor the rail to the tie
- To provide an electrical insulation gap in the circuit
- To measure the gauge between rails
Correct answer: To connect two rail ends mechanically and maintain vertical and horizontal alignment
Joint bars clamp the web of two adjoining rails to transfer load across the joint and keep rail ends aligned.
Question 2: What is 'gauge' in the context of railroad track?
- The distance between the inside faces of the two running rails, measured 5/8 inch below the top of rail (Correct answer)
- The weight of rail per yard
- The height of the rail head above the tie plate
- The thickness of the rail web
Correct answer: The distance between the inside faces of the two running rails, measured 5/8 inch below the top of rail
Track gauge is the distance between the inside faces of the rail heads, measured 5/8 inch below the rail top; standard gauge in the US is 4 feet 8½ inches.
Question 3: A turnout (switch) consists of which three main components?
- Switch points, frog, and closure rails (Correct answer)
- Rail, ties, and ballast
- Spikes, tie plates, and bolts
- Guard rails, bridge ties, and anchor plates
Correct answer: Switch points, frog, and closure rails
A turnout's three main elements are the switch (points), the closure rails connecting to the frog, and the frog where the two routes cross.
Question 4: What is the purpose of a guard rail (check rail) installed at a frog?
- To keep the wheel flange on the correct path and prevent it from taking the wrong route through the frog (Correct answer)
- To provide additional weight for stability
- To measure the flange depth of passing wheels
- To electrically isolate the two tracks at the crossing
Correct answer: To keep the wheel flange on the correct path and prevent it from taking the wrong route through the frog
Guard rails are placed opposite the frog point to guide the wheel flange and ensure wheels traverse the frog correctly without derailing.
Question 5: Rail cant (inclination) on most North American railroads is set at:
- 1 in 40 (toward the track center) (Correct answer)
- 1 in 10 (toward the field side)
- Perfectly vertical (0 degrees)
- 1 in 20 (toward the field side)
Correct answer: 1 in 40 (toward the track center)
Rail is inclined at 1:40 toward the track center so the rail head matches the conical tread of the wheel for optimal contact and wear distribution.
Question 6: What does the term 'superelevation' (cross-level) refer to in track geometry?
- The elevation of the outer (high) rail above the inner (low) rail on a curve (Correct answer)
- The height of the rail above sea level
- The difference in rail weight between two track segments
- The vertical profile of the track over a summit
Correct answer: The elevation of the outer (high) rail above the inner (low) rail on a curve
Superelevation raises the outer rail on a curve to counteract centrifugal force on passing trains, improving stability and ride quality.
CTB CTB Track Systems & Components 1
What is the primary function of a rail joint bar (fishplate) in a track system?