Woking Junction

How many men does it take to add a new power cable. Upgrading the power supply to allow longer commuter trains, at present 12 is the maximum number of coaches travelling to London, but most are 4 - 8. Never thought about it but its like a big train set and only few can traverse a section at the same time, something to do with voltage, resistance and all that. Much better when the weekly steam train passes this section.