The Q&As for Railway Workers

1. What issues should be considered when setting the superelevation value of the outer rail?

Answer: The premise should be to ensure the safety of driving. The superelevation of the outer rail should not be too small. It is necessary to ensure that when the train passes at a higher speed, derailment and overturning accidents will not occur due to centrifugal force; the superelevation of the outer rail should not be too large. The centripetal force generated during the curve, even if there is a sideways wind, there is no danger of inward overturning.

 

2. The maintenance of seamless lines must be "one-point", "two-clear", "three-test", "four-no-exceed", "five-no-go". What is the specific content of "five don't go"?

Answer: Do not leave without backfilling the track bed, do not leave without tamping after operation, do not leave without organizing a return inspection, do not leave if the quality of the line does not meet the operation standard, and do not leave until abnormal situations occur.

 

3. What is a vertical curve?

Answer: When changing from one slope to another on the longitudinal section, or connecting a flat slope with a slope, when the algebraic difference of the slope is greater than a certain value, the middle must also be connected by a curve. This kind of curve is generally called a vertical curve.

 

4. What are the basic requirements for straightening the curve with the rope method?

Answer: ⑴ If the straight line at both ends of the curve is in bad direction, it should be corrected in advance; when the straight line between the two curves is short, it can be corrected at the same time as the two curves.

⑵Measure with a steel ruler on the outer strand rail, and set a measuring point every 10m (whether the head and tail of the curve are on the measuring point is not limited).

⑶ Under the condition of low wind force, measure the positive vector of each measuring point by pulling the rope, measure 3 times, and take the average value.

⑷Calculate the channel amount according to the rope method, and it is not advisable to adjust the plan positive vector in a large amount in order to reduce the channel amount during calculation.

⑸Set up the road-setting piles, and press the piles to dial the road.

 

5. What is the curve "goose head"? ​

Answer: The "goose head" of the curve means that the head or tail of the curve deviates from the proper plane position, protrudes outward of the curve, and goes beyond the straight line to form a small reverse curve, which looks like a "goose head".

 

6. What is the joint "spout"?

Answer: "Spout" means that the rail joint on the curve leaves the proper arc position and protrudes to the outside of the curve.

 

7. How is the actual maximum superelevation of the curve specified?

Answer: The actual set maximum super height shall not be greater than 125mm on a single line. It must not be greater than 150mm on the double line.

 

8. How are the unbalanced under-superelevation and over-superelevation allowed?

Answer: The unbalanced superelevation should not be greater than 75mm, and it should not be greater than 90mm under difficult conditions, but the superelevation of 90 (not included) to 110mm that has been set under certain special circumstances can be temporarily reserved. , but should be gradually modified; the unbalanced superelevation should not be greater than 30mm, and should not be greater than 50mm in difficult cases, and should not be greater than 70mm in some special cases where the allowable speed is greater than 160km/h.

 

9. How is the total error of the ordinary line rails determined?

Answer: The rail joints should be set evenly. The total error of the rail joints per kilometer of the line shall not be greater than 80mm for a section of 25m rail; and shall not be greater than 160mm for a section of 12.5m rail. The rail gap of the insulating joint shall not be less than 6mm.

 

10. Why is it necessary to perform rail seam inspection?

Answer: The standard size of the rail joint should be calculated and determined according to the formula stipulated in the "Railway Line Repair Rules". If the rail gap is too large, it will not only add extra impact and resistance when the train passes, and accelerate the destruction of the track structure, but also may bend or shear the splint bolts when the temperature drops. If the rail gap is too small, blind seams will form when the rail temperature rises. At this time, when the rail temperature continues to rise, a lot of pressure will be generated inside the rail, and the track may expand.