What is adhesion in locomotive?
• Adhesion is the ratio of drawbar force to locomotive weight. • The “dispatchable adhesion” is the overall adhesion rating. – a measure of how much a locomotive can pull.
What is adhesion limit?
Effect of adhesion limits Fmax= coefficient of friction × Weight on wheel. For steel on steel, the coefficient of friction can be as high as 0.78, under laboratory conditions, but typically on railways it is between 0.35 and 0.5, whilst under extreme conditions it can fall to as low as 0.05.
How does the coefficient of adhesion affect the performance of electric traction?
Coefficient of Adhesion in Traction decreases with increase in speed. The nature of variation is shown in Fig. When a wheel slips, the speed of driving motor increases. The torque drops by a large amount in motors with low regulation of speed and the wheels regain their grip on rails immediately avoiding slip.
How do locomotives increase traction?
Trains get traction because of the immense weight of the locomotives, and the friction generated between the wheel and rail head. To assist with gaining traction, many modern locomotives are equipped with traction control systems, which will control the amount of tractive effort applied to the rail head.
What is the maximum grade that an adhesion railroad can climb?
An adhesion railroad can only climb grades of 4 to 6%, with very short sections of up to 9%. A “rack” railroad can climb grades of up to 48%, depending upon the type of rack system employed.
What is the factor of adhesion?
the ratio of the force that can be exerted on driving wheels with full traction to the weight on the driving wheels, usually expressed as a percentage. Also called adhesion, adhesive factor.
What is the normal value of adhesion friction?
Coefficient of adhesion (μ): It is defined as the ratio of the tractive effort (Ft) to propel the wheel of a locomotive to its adhesive weight (W). The normal value of the coefficient of adhesive is 0.25.
Which braking system on the locomotives is costly?
In case of electric locomotives, additional equipment should be needed for the provision of regenerative braking, it will increase the overall cost of installation. It is costlier compared to other braking systems used in steam and diesel locomotives.
How do freight train pull so much?
Locomotives can pull massive weights due to these bad boys. Hydraulic dampers, essentially large springs. There are springs behind the disk shaped things, and also behind the hook. Its to cushion the forces.
Are train tracks oiled?
The primary function of rail lubrication is to minimize friction between the wheel flange and rail interface, especially in the curves where side cutting of rails often occurs. The routine application of rail lubrication, however, will increase the life expectancy of these rails.