Provided is a rail that is effective in improving wear resistance and rolling contact fatigue (RCF) resistance. The rail has a metallic structure including a pearlitic structure and a structure other than the pearlitic structure in a surface layer from a surface of a rail head to a depth of at least 0.5 mm, where the pearlitic structure has Vickers hardness of 420 HV or more and 520 HV or less, and the structure other than the pearlitic structure has Vickers hardness of 350 HV or more and 420 HV or less.

Provided is a rail that is effective in improving wear resistance and rolling contact fatigue (RCF) resistance. The rail has a metallic structure including a pearlitic structure and a structure other than the pearlitic structure in a surface layer from a surface of a rail head to a depth of at least 0.5 mm, where the pearlitic structure has Vickers hardness of 420 HV or more and 520 HV or less, and the structure other than the pearlitic structure has Vickers hardness of 350 HV or more and 420 HV or less.

A surface-seamless steel rail is provided in the present invention. Said surface-seamless steel rail includes a right connecting part located on one side of said steel rail, a left connecting part located on the other side of said steel rail, and a seamless spring piece located on the top side of said steel rail. Both said left connecting part and said right connecting part include a plug portion in embedded engagement with each other. Said seamless spring piece includes a fixed portion at one end and a free portion at the other end, said fixed portion is fixedly connected on top side of said plug portion of one of said left connecting part and said right connecting part. The other of said left connecting part and said right connecting part is provided with an arc-shaped channel at its interior body, said free portion of said seamless spring piece is suitably inserted into said arc-shaped channel.

A surface-seamless steel rail is provided in the present invention. Said surface-seamless steel rail includes a right connecting part located on one side of said steel rail, a left connecting part located on the other side of said steel rail, and a seamless spring piece located on the top side of said steel rail. Both said left connecting part and said right connecting part include a plug portion in embedded engagement with each other. Said seamless spring piece includes a fixed portion at one end and a free portion at the other end, said fixed portion is fixedly connected on top side of said plug portion of one of said left connecting part and said right connecting part. The other of said left connecting part and said right connecting part is provided with an arc-shaped channel at its interior body, said free portion of said seamless spring piece is suitably inserted into said arc-shaped channel.

An example track system includes: a supporting structure; ballast supported by the supporting structure; a plurality of track ties supported by the ballast; a pair of rails supported by the plurality of track ties; and a layer of rubberized asphalt coating disposed as an interface between the ballast and the supporting structure, the rubberized asphalt coating having bituminous binder, crumb rubber particles, and small gradation hard rock aggregate; wherein resiliency of the layer of rubberized asphalt coating permits particles of the ballast in direct contact with the layer of rubberized asphalt coating to move elastically relative to each other while inhibiting abrasion of adjacent ones of the particles of the ballast against each other and against the supporting structure.

An example track system includes: a supporting structure; ballast supported by the supporting structure; a plurality of track ties supported by the ballast; a pair of rails supported by the plurality of track ties; and a layer of rubberized asphalt coating disposed as an interface between the ballast and the supporting structure, the rubberized asphalt coating having bituminous binder, crumb rubber particles, and small gradation hard rock aggregate; wherein resiliency of the layer of rubberized asphalt coating permits particles of the ballast in direct contact with the layer of rubberized asphalt coating to move elastically relative to each other while inhibiting abrasion of adjacent ones of the particles of the ballast against each other and against the supporting structure.

Proposed are the welding conditions under which welds are always stably formed such that the difference in hardness between flash-butt welds and rail base metal and the deflection in a bending test are in better ranges. A plurality of pieces of rail base metal are joined via welds formed by flash-butt welding, where the rail base metal has a chemical composition containing C: 0.60 to 1.20 mass %, Si: 0.10 to 1.50 mass %, Mn: 0.10 to 1.50 mass %, and Cr: 0.10 to 1.50 mass %, with the balance being Fe and inevitable impurities, and the flash-butt welding is performed with an amount of welding heat input of 1.50×10.sup.5 kA.sup.2×sec or more and 4.50×10.sup.5 kA.sup.2×sec or less.

Proposed are the welding conditions under which welds are always stably formed such that the difference in hardness between flash-butt welds and rail base metal and the deflection in a bending test are in better ranges. A plurality of pieces of rail base metal are joined via welds formed by flash-butt welding, where the rail base metal has a chemical composition containing C: 0.60 to 1.20 mass %, Si: 0.10 to 1.50 mass %, Mn: 0.10 to 1.50 mass %, and Cr: 0.10 to 1.50 mass %, with the balance being Fe and inevitable impurities, and the flash-butt welding is performed with an amount of welding heat input of 1.50×10.sup.5 kA.sup.2×sec or more and 4.50×10.sup.5 kA.sup.2×sec or less.

A rail including a predetermined chemical composition is provided, in which 90 area % or greater of a metallographic structure in a cross section of a rail web portion is a pearlite structure, a minimum value of a hardness in the cross section of the rail web portion is Hv 300 or greater, and a difference between a maximum value and the minimum value of the hardness in the cross section of the rail web portion is Hv 40 or less.

A rail including a predetermined chemical composition is provided, in which 90 area % or greater of a metallographic structure in a cross section of a rail web portion is a pearlite structure, a minimum value of a hardness in the cross section of the rail web portion is Hv 300 or greater, and a difference between a maximum value and the minimum value of the hardness in the cross section of the rail web portion is Hv 40 or less.