Have you ever noticed the lights flickering or briefly going out while traveling by train, especially at station stops or just before departure? This is standard in train travel and typically isn’t a concern. Understanding why passenger train lights malfunction can help you feel better prepared and more at ease on your next journey, whether you’re riding Amtrak in the USA, VIA Rail in Canada, or another passenger train.
Efficiency: one reason why passenger train lights go off
At a station, efficiency is the primary reason lights turn on and off.
Passenger locomotives generate head-end power (HEP), also known as hotel power, to supply lighting, heating, air conditioning, and electrical outlets.
HEP is excellent for traveling down the rails, but it is less efficient during long station stops when other power sources are available.
Most stations where trains sit for a while have “house power,” which allows staff to plug the train in and use the station’s power instead of HEP.
This process reduces railroads’ costs by lowering fuel consumption and minimizing equipment wear, as trains no longer need to operate the HEP generator.
When trains switch from “house” to HEP or vice versa, the lights will go off as they are unplugged from one source and plugged into another.
Each car has a battery backup system to power the emergency lights and PA system. This system often engages for a few moments during the power swap.
If you are on the train during this period, specific services, such as toilets and food cars, may be unavailable.
Equipment changes can cause passenger train lights to go off
Occasionally, the train may not have power at stops.
Equipment swap
If you have ever traveled through Washington, D.C., on a long-distance train, you have likely experienced a period when the power was out.
During this time, the train has no power for employee safety.
Sometimes, the Cardinal hauls extra equipment between Chicago and the Beech Grove repair center. While Amtrak adds or subtracts equipment, the lights go off until the work is finished.
Combining trains
A few trains may separate or merge en route, and, as with equipment swaps, the train will not have power.
Passenger train lights go off during some safety checks.
Sometimes, trains must undergo safety checks; during these tests, engineers may need to temporarily shut off power to the passenger cars.
Squeeze out a little more power!
Locomotive engineers sometimes disable the HEP if the train requires more power. The HEP can reduce the power to the traction motors that power the train.
If engineers need to do this, it is for a very short time.
Good night!
If it’s late at night and the lights go out and don’t come back on, it could be because it’s nighttime.
Amtrak turns off the lights in coach cars at night so passengers can sleep.
There are nightlights at night. Do not try to tamper with them; yes, I have seen this. You may want to use an eye mask if you need complete darkness to sleep while traveling.
I got unplugged!
Passenger cars transfer power from one car to the following via cables; these cables may come loose during travel, causing a loss of electrical power. Once the train stops, the crew can reconnect the line, and everything returns to normal. If this happens, don’t worry; all the safety equipment still works.
Passenger train lights on electric trains.
Today, your adventure could be powered by a diesel or electric locomotive; electric locomotives predate diesel locomotives.
Electric trains get power in one of two ways: through overhead wires or a third rail.
How electric trains give you power
Electric trains do not use the same head-end power (HEP) systems as diesel trains; instead, they use a converter that reduces the voltage to supply household power.
Block issues
A “dead block” occurs when the power source, such as an overhead line or third rail, is disconnected from the electrical supply.
Regardless of where an electric train draws power, it may encounter a dead block on the tracks.
Railroads divide power lines into blocks, either by wires or by rails, so that work on one section can proceed without shutting down the entire line.
Railroads may intentionally create a dead block for maintenance; in such cases, they will not send trains along those tracks. Other reasons include acts of God or accidents; in those cases, a train could run into a dead block if it isn’t warned immediately. But this would rarely happen.
Third-rail train power issues
An example of third-rail power is Chicago’s CTA Subway and Elevated Lines. Each car makes contact with the third rail to receive power.
A train may lose power when going through a switch or crossing another track because the car loses contact with the power rail.
Power will be restored as soon as the car passes through that area.
Overhead Wires
Other electric trains use overhead wires; examples include the South Shore Line, Amtrak’s Northeast Corridor, and San Francisco’s streetcars.
Power loss can occur if these trains lose contact with the overhead power supply.
Wrap-up on passenger train lights
I hope this answers your question about why interior lights on passenger trains go on and off.
On a Metra train to Chicago, the “hotel power” went off after a cable became loose and disconnected.
Since we weren’t in danger, they waited until we arrived at Chicago Union Station to resolve the issue, since we were close.
It is fun to hear first-time train travelers gasp when it happens. You can share this information with your travel companions.
Safe travels!
Kev
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