Where does the electricity off the train lines go? .... why do they keep it going through the night?

Question

ok, hypothetically, if trains run from 9-5 yet the circuit runs 24/7 - what happens to the excess energy?

Answer 1

It does not 'go'. If there is no train closing the circuit there simply is *no* current.

It's the same as if you remove the bulb from your lamp and the switch it on. No bulb -> no circuit -> no electric current.

There is however an 'excess' in the sense that the power plants can be throttled or even switched off completely if there is no load. Of course they need to be activated again when the trains start to move in the morning. This is true not only for the railways but for any electric grid and it needs accurate forecasts to adjust the energy production exactly to the consumption at the right moment. With railroads this is rather simple since the trains are operating on schedule.

Answer 2

I didn't know trains ran off electricity. They always ran off diesel or coal. Trams run off electricity though.

Answer 3

If the trains were to run from 9-5 but the line were kept live 24/7 you would have a situation where the potential is being generated but not being used.

If this were the case then I imagine the railway authorities would either shut down the power once the trains stopped running or sell the power to the grid and make some money.

In reality however trains start early in the morning (6.00am or earlier) and run until late at night (11.00pm or later), and some run into the early hours. On a main line it is unlikely the current would be switched off unless it was necessary for maintenance purposes.

On the London Underground the current is switched off between the last train at night and the first train the following morning, leaving a space of approx. 6 hours during which the maintenance crews operate. They use battery-powered trains which are charged up in the daytime ready for the next turn of duty.

Answer 4

The electricity people supply the voltage, it's always there.

(It's 230 volts in your house, 25kV for the trains).

Whether the customer draws off current by applying a load is up to them, i.e. by turning appliances (or train motors) on or off.

The electricity supply people monitor the current taken and turn on or off their generating plant, as required, to be able to supply the load current.

Answer 5

James Thurber penned a famous cartoon showing the lady frightened of the electricity leaking out of her plugs...

Answer 6

I'm sorta lost by your question.

But trains run day and night, so electric trains would need electricity day and night, if that is what you asking.

Answer 7

Just think of it like your house.It's there if you need it but if everything is turned off your not using any.

Answer 8

Some of the answers here have been very silly, whether it is overhead wires or track power simply depends where you live.

No power is used if there is no train running. As someone said, take a bulb out in your house, no current drain. You don't switch your main box of at night, do you?

You need to complain about your teacher if they can't answer such a simple question.

Answer 9

I just spent the day on an overhead line car, doing maintenance of overhead trolley wire with the 600V power on.  The line car needs the 600V power to move around. The car and platform are made of wood, so it's insulated.  As long as I don't touch ground, I'm OK.  

Electric power works like water pressure.  There's water pressure in your house 24x7 so it's always there when you open a faucet.  You're not using any water, but the pressure is always there.  Electricity is the same, your power socket is "hot" 24x7 and will shock you even if your electric meter isn't turning.  Same with electric railroads.

"Surely they must turn the power off" is often wishful thinking by stupid trespassers...

One reason they don't is that to minimize power loss, they have many feeder substations, and each substation would have to be turned off individually.  You'd think "Well today, they can just remote control it" - not necessarily.  Railroads are very conservative with technology, and a lot of this stuff went in 20-50 years ago.  There were parts of the US Northeast that were using 25-cycle power into this decade (normal is 60-cycle).  

For instance some railroads used "automatic substations" designed to help with power distribution.  The first ones were mechanical, so they didn't run them unless needed.  They were automatic because they were designed to spin up and come online if the line voltage sagged too low, and shut down after 10 minutes of low current flow (disuse).  

Suffice it to say there's not a big red switch.  There's a whole bunch of them, and it takes technicians in the "lines and substations" craft to know how to do it right.  So most of the time, work crews just assume the power is on and work around it, rather than go through all the procedures to formally get it turned off and locked out.

Answer 10

If your science teacher can't explain this to you, then your science teacher has a promising future in the fast food industry.

Electricity is in potential form when trains are not using it.  There is a voltage potential between the overhead wire and the rails, but no power is consumed until the motor of an electric locomotive or an electric rail car is connected between those conductors.  So there is no waste energy--only what is actually used.

Answer 11

Technically there really isnt any excess energy. Energy only flows when a train is using the lines. Also the power lines arent 1 big circuit. They are made up of many switchable 'sections' , this is to distribute the load from the trains evenly over the network.

The trains are out of service four about 5 hours per day. It would take longer than this to turn off and on each individual 'section' of overhaed, mainly due to all the checks that need to be done before and after a turn off, and its all done manually.

e.g. the tyne and wear metro runs at 600V. There can be up to 80 trains running at any one time over the whole network. Each train, full loaded with passengers, can draw over 500amps when pulling away from a standstill, so  that adds up to an awful lot!!

Answer 12

It's in the overhead cables, not in the lines.

Apart from the heat loss, without a train running there's no energy being wasted when there's no train running, as no circuit exists.

And trains run thru the night - freight trains.

Answer 13

The electricity does not go anywhere, unless a train is moving along the track. It is safe to stand on a conductor rail with both feet, but as soon as you put one foot on the train rail....pooooooof!!!!!!!!!!!!!!!