turnout crawling scene

What’s Up with Turnout Crawling?

Turnout crawling is actually a popular saying, also known as turnout movement, which means that a certain part of the turnout has a certain displacement relative to other parts, exceeding the standard value, which is a common turnout disease.

Turnout crawling can be divided into relative crawling and absolute crawling. Relative crawling refers to the fault between the internal components of the switch, the switch inside the switch, and the switch end of the two strands of rail joint rail end of the fault is more than the “railway line repair rules” provisions. The provisions pointed out that the tip of the switch and the two points of the rail should not be more than 20 mm. Absolute crawling means that the whole lease is wrong relative to the laying position of the top surface, and the longitudinal movement occurs in the straight direction. According to regulations, the longitudinal displacement of seamless switches shall not exceed 10 mm, and the longitudinal displacement of non-seamless switches is not clearly defined and standardized. The absolute crawling of turnout is an objective existence, and it is also a disease that maintenance is not easy to solve.

The crawling of the switch includes: the point of the switch is not square, and the rail seam at the heel of the switch is not square; the basic rail joint and the straight curved strand joint after the fork center are not square; the bolt at the root of the switch rail is crooked, the pull rod of the switch rail and the connecting rod are crooked; the rail seam is not normal, continuous large seam or blind seam, and the anti-climb device often fails.

How to measure basic rail creep?

Railway field workers usually use railway square feet for turnout crawling measurement. Place the T edge of the railway square foot on the straight basic rail, align one side of the square foot with the tip of the basic rail(at the front rail head of the switch), and observe whether the other side of the square foot is aligned with the tip of the basic rail(at the front rail head of the switch). if the alignment indicates that the basic rail is not crawling(not misaligned); if the alignment indicates that the basic rail is crawling(two basic rails are misaligned).

The harm of basic rail crawling to switch equipment

The crawling of the basic rail will cause the turnout to be out of square and the sharp rail to crawl, which will easily cause the following hazards:

One is that it is easy to cause to gap change of the turnout. The amount of change in the gap of the turnout is as follows:

Second, it is easy to cause the indicator rod and the action rod of the switch machine to be mocha with the square hole sleeve and the round hole sleeve on the side of the switch machine is not flexible, and it is easy to cause the turnout to run idly, and the square hole sleeve and the round hole sleeve of the switch machine are worn and water ingress.

Third, it is easy to cause close-fitting rods, display connecting rods, and improper installation devices.

Fourth, it is easy to cause the inner display rod to break.

What are the laws of turnout crawling?

Affected by ambient temperature and thermal expansion and contraction, the number of crawling detections recorded in the future for the turnouts installed when the temperature is the lowest in winter is in the direction of increasing. Conversely, the recorded data of the turnouts installed in the summer when the temperature is the highest is in the direction of shortening. Only according to the recorded data can it be possible to obtain the “zero point” position of the turnout’s creeping, and analyze creeping law.

What remedial measure are there for point rail crawling?

A patch can be inserted into the gap of the anti-climbing limiter of the switch rail, and the crescent crawler can also be installed in the bolt hole of the switch rail joint. In addition, the fastener bolts behind the switch rails can also be tightened.

In the daily use of the turnout, it is necessary to carry out comprehensive maintenance on a regular basis, eliminate the hanging plate of the dark pit, loosen and unload various spare parts, and fully oil all the spare parts, adjust the joint track seam, and eliminate the eyebrow edge of the rail joint, grinding smooth saddle joints and wavy wear rail surfaces. In addition, attention should also be paid to welding and repairing the vertical grinding part of the fork center in time, and grinding the tread surface of the fork to be smooth.