Engineer Electric Railway case studies
Engineer Electric Railway · Put your knowledge to work in context.
Electric Railway Engineer is a professional credential for engineers who design, commission and maintain the electrical infrastructure that keeps electric railways running - traction substations and feeders, overhead contact lines, rolling-stock electrical equipment, signalling interfaces and supervisory control. It suits operator and utility engineers, consultants, rolling-stock electrical specialists and maintenance supervisors moving into system-level responsibility. The Engineer Electric Railway case studies are 5 cases and about 3,930 words.
1DC branch voltage collapse and rectifier loading after peak service increase
An existing 1500 V DC traction system supplies a 12 km single-track branch from one substation equipped with two 2500 kW rectifiers. The design minimum pantograph voltage is 1000 V, and each rectifier is rated for 150% load for 2 hours.
787 words, about 4 min2Contact wire wear and arcing after loss of tension at a tunnel portal
A 25 kV, 50 Hz overhead contact line has a design contact-wire tension of 12 kN and stagger of ±200 mm. After a hot spell, a track inspection finds the balance weight of one tensioning device resting on its stop, with measured tension 8.5 kN at 32°C.
825 words, about 4 min3Regenerative braking overvoltage on a line with no receptive load
A 1500 V DC suburban line uses 6-car EMUs with regenerative braking. The traction converter trips regenerative braking when line voltage exceeds 1800 V and blends to friction braking; there are no braking resistors.
821 words, about 4 min4Track circuit false clear after ballast renewal and heavy sanding
A 4-aspect signalling section uses audio-frequency track circuits with a design ballast resistance of 3.0 Ω·km. Following ballast cleaning and a long dry spell, measured ballast resistance in one 800 m section falls to 1.3 Ω·km.
752 words, about 4 min5Stray current and failed drainage at a 750 V DC depot
A 750 V DC metro depot is fed by a rectifier whose negative is connected to the running rails. The 1.2 km depot track is ballasted and the rails are insulated from earth, but a survey over 800 m measures rail-to-earth resistance of 1.5 Ω·km against a design target of 10 Ω·km.
745 words, about 4 min