Articles published in the issue 09, 2020

Inter-repair deadlines: is it possible to increase them?

Keywords: inter-repair service life, intermediate types of repairs, specific output of rails, areas of rational use of rails.

Vasileva Svetlana — leading engineer of the regulatory and methodological Department of road and structures management of the Central infrastructure Directorate JSC «Russian Railways». E-mail: ryndinavasiljeva@mail.ru

Borts Alexey — Ph.D., deputy Director of the scientific center «Rails, welding, transport materials science» JSC «VNIIZHT». E-mail: borts@list.ru

Abstract. The article presents the results of analysis showing a high degree of correlation between the volume of capital repairs and indicators of weighted average tonnage, the number of withdrawn defective and acute-defective rails, the number of fractures.

The efficiency of intermediate types of repairs that reduce the specific output of rails by up to 30 %, even with an increase in the missed tonnage, is shown.

The possibilities of improving inter-repair resource indicators and reducing the length of track sections with overdue major repairs due to the implementation of inter-repair schemes and areas of rational and effective use of rails of various categories are identified.

Рrestressing concrete of beam construction

Keywords: prestressed concrete, beam construction, a tension of armature on emphasizes (pre–tension), a tension of armature on concrete (post–tension), a mechanical method of a tension of armature, anker devices, bridge superstructures strengthening, monostrand, external reinforcement, unbonded.

Kaptelin Sergey — Ph.D., associate Professor, head of laboratory of the Bridge Department of St. Petersburg State Transport University Emperor Alexander I. Saint-Petersburg, Russia. E-mail: kaps1962@yandex.ru

Marchenko Maxim — Civil Engineering Design Director JSC «Institute of Post-tensioning Technologies». Moscow, Russia. E-mail: mms2000@inbox.ru

Abstract. Application of prestressing of high-strength steel is the most effective way to increase reliability and durability of superstructures of reinforced concrete bridges, roof and floor structures of buildings, railway sleepers, crane beams, culverts working under pressure and other transport structures.

The most advisable is a prestressing of reinforced concrete in beam structures that work on bending. This is explained by the possibility of preventing the formation of cracks in the tension zone of the cross section, which eliminates the risk of corrosion, reduces steel consumption and increases beam stiffness.

The creation of prestressing in reinforced concrete structures is a complex technological process, the improvement of which remains relevant at present. In addition, new materials appear, for example, high-strength steel strands in a polymer protective sheath, which greatly expand the application of prestressing technology, allowing you to use it not only in the manufacture of reinforced concrete structures, but also during their repair, reinforcement and reconstruction.

Machine methods for measuring and straightening the track

Keywords: automation for machine shift of a way, geodetic methods, railway machines.

Andrianov Oleg — General Director Eurotech LLC. Saint-Petersburg, Russia. E-mail: ooo_eurotech@mail.ru

Abstract. The article is devoted to a brief analysis of existing methods of machine measurements of the spatial position of a railway track, existing methods of straightening a track, and studies of promising methods of measuring and straightening a track. It is shown that there are new, unexplored methods for the joint use of geodetic automated methods for measuring the position of a track and its machine alignment in real time. The alignment of the path in the 21st century should be developed according to a combined model that allows you to simultaneously determine the spatial position of the path and produce it in its design position, taking into account its disorders, and not to separate these processes in time.

The main advantage of the new model is the content of the track parameters in a strict design position without preliminary measurements, calculations and optimizations of the new track project, depending on its existing state.