18 ms·
Overhead only. But 3rd rail for long distances is really dangerous. Subways and metros use it since they typically strongly control access to the tracks and tun
by theluketaylor 3y ago
Overhead only. But 3rd rail for long distances is really dangerous. Subways and metros use it since they typically strongly control access to the tracks and tunnels, but that really isn't possible when crossing whole countries.
- wkat4242 3y agoStill, you could use third rail in tunnels which can be tightly controlled, and overhead elsewhere. Dual trains exist, many metros have it too.
- rjmunro 3y agoIn the UK, 3rd rail is typically 600V (DC), where as overhead is 25kV (AC). So you need 40× the current to get the same power. For high powered intercity trains that run at around 1MW of power, it increases transmission losses substantially.