In railway terminology, ordinary anti-corrosion sleepers are also divided into two types: first type anti-corrosion sleepers and second type anti-corrosion sleepers. Many people subconsciously think that when they hear "Type 1" or "Type 2", Type 1 is definitely better and of better quality than Type 2. Actually, this is a common misconception. The main difference between them is that, just like we buy clothes in different sizes, the key lies in the different specifications and sizes, which determine their use in different positions on the railway. Their quality requirements, especially the standards for anti-corrosion treatment, are completely consistent.
In today's widely used concrete sleepers, wooden sleepers (mainly pine sleepers that have undergone anti-corrosion treatment) still occupy an important position in the railway system, especially in some specific scenarios. This is mainly due to several natural advantages of wood:
1. Good elasticity: Wood itself has a certain degree of elasticity and toughness, which can effectively absorb the impact and vibration generated during train operation, making the train run more smoothly, passengers feel more comfortable, and reducing damage to the track structure.
2. Strong insulation: Wood is an excellent insulator, which is crucial for railway signal systems to effectively prevent short circuits in track circuits and ensure train safety.
3. Easy to process and lay: Compared to heavy concrete sleepers, wooden sleepers are lighter, making them relatively easy and labor-saving for production, processing, transportation, on-site laying, maintenance, and replacement.
4. Good combination with ballast: The surface of the wooden sleeper is relatively rough, and the friction between it and the ballast (gravel) is greater, which can provide better track stability.
Type 1 and Type 2 Sleepers: Size Difference
Now back to the focus: Type 1 sleepers and Type 2 sleepers. Their difference lies in their size specifications:
A type of sleeper: Its dimensions are 160mm (width) x 220mm (height) x 2500mm (length). You can understand it as being more 'robust', with larger width and height.
Class II sleepers: Their dimensions are 145mm (width) x 200mm (height) x 2500mm (length). Compared to a type of sleeper, it is slightly "slimmer" in both width and height.
Both have a standard length of 2500 millimeters (2.5 meters), which has been determined through long-term practice and is suitable for the spacing requirements of most tracks.
Why do we need different specifications? Usage determines selection
Since the quality (mainly anti-corrosion performance) requirements are the same, why do we need to make two sizes? The principle is simple: when used in different places, the burden borne varies.
1. A type of sleeper (160x220): Because it is wider and taller, with a larger cross-sectional area, its load-bearing capacity and bending strength are also greater. It is mainly used for:
Railway mainline: This is the busiest, fastest, and heaviest track for trains. The main line requires the most stable support, and a type of sleeper is the main force.
Throat area of station track: a key area where turnouts are concentrated within the station, where trains frequently enter and exit and the track is subjected to complex forces, requiring stronger support.
On bridges: The tracks on bridges require extremely high stability and load-bearing capacity, and usually use a type of sleeper.
Curves with smaller radius: When a train passes a bend, the lateral pressure on the outer track is greater, requiring stronger sleepers to resist this lateral force.
2. Type 2 sleepers (145x200): Although slightly smaller in size, after the same rigorous anti-corrosion treatment, their strength is fully sufficient for certain scenarios and more economical. It is mainly used for:
Non throat areas of station tracks: such as arrival and departure tracks, freight tracks, shunting tracks, etc. within the station. These lines have relatively low train speeds, longer stopping times, and lower loads compared to the main line.
Dedicated lines and factory mine lines: These lines usually have a small capacity and low operating speed. The use of second-class sleepers can meet the demand while saving costs.
Part of the main line auxiliary lines with lower speeds: In some secondary main lines or sections with low speed requirements, second-class sleepers may also be used.
Replacement parts during line maintenance: Sometimes, Class II sleepers are temporarily used as substitutes during main line maintenance.
Simply put:
A type of sleeper with a larger size (160x220) and stronger performance is used in places where trains run fast, carry heavy loads, and are critical to the track (main roads, bridges, and critical turnouts).
The size of the second-class sleepers is slightly smaller (145x200), and they are suitable for use in areas where trains run slower, load less, and are not as core (such as internal station lines, dedicated lines, etc.).
Both Class I and Class II undergo the same rigorous anti-corrosion treatment process before leaving the factory, ensuring long-term service in harsh railway environments and resistance to decay and insect infestations. Their "grade" classification reflects the differences in design bearing capacity and applicable scenarios, rather than the quality of anti-corrosion or basic wood quality.
summarize
So, next time you see a type of sleeper or a type of sleeper, don't doubt which one is "better". They are like tools of different sizes, each with its own place to use. A type of sleeper with a large size, specifically designed to carry heavy loads, is used on the most critical and heavily stressed main railway lines. Class II sleepers are "one size smaller" and have good performance. They are used in stations or dedicated lines with slightly lighter loads, ensuring safety and reliability while also reflecting economy. Their core value lies in the elasticity, insulation, and durability provided by pine wood that has undergone scientific anti-corrosion treatment. The key to distinguishing them is the different load-bearing requirements corresponding to the size difference of over ten millimeters.
