LocomotiveThe powered vehicle that pulls the train, often just called the engine. The federal rules define it as on-track equipment with one or more propelling motors, built to move other equipment.
Passenger car (coach)Carries the riders. British railways call it a carriage. The federal rules define a passenger coach as equipment for the public with no propelling motors and no control stand.
CabThe space where the engineer sits at the control stand. The federal rules ask for cab windows that give an undistorted view of the track. A hood unit has a single cab, and the crew can see well enough from it to run in either direction.
HeadlightFederal rules ask for a peak of at least 200,000 candela. It is aimed to light up a person at least 800 feet ahead. North American locomotives carry two lamps in case one fails.
HornAn air horn fed from the main air reservoir. Federal rules set its sound between 96 and 110 decibels, measured 100 feet ahead. The pattern at a public crossing is two long, one short, one long.
Coupler (knuckle coupler)Locks onto the one on the next vehicle when pushed together. Nobody has to stand between them. Patented by Eli Janney in 1873, it is shaped like a right hand with curled fingers. Every vehicle has one at each end.
Truck (bogie)A frame that holds the wheelsets and swivels under the body. This lets a long vehicle follow a curve. This locomotive rides on two, with three axles each, and the coach on two with two axles each. Bogie is the British word.
WheelSteel on steel rolls with very little friction, which makes trains efficient. Two wheels fixed to one axle make a wheelset, and both turn together.
Side doorWhere riders get on and off, at the end of the car. Since April 5, 2016 the federal rules have required the exterior side doors of a passenger train to be closed while it moves between stations, with a few exceptions for the crew.
WindowSome of them are also exits. The federal rules define an emergency window as part of a side window built to be removed quickly and easily from inside the car in an emergency.
Locomotive: front end and cab 5
Short hood (nose)The part of the body between the cab and the nearer end. It was added to protect the crew in a collision, and from the late 1950s it was built lower so the crew could see over it. The long body behind the cab is the long hood.
Ditch lights (auxiliary lights)Two white lights that form a triangle with the headlight. They make the train easier to spot. Required in the United States since December 31, 1997 on lead locomotives that cross public roads at more than 20 mph.
Pilot (cowcatcher)Deflects obstacles before they reach the wheels. On a lead locomotive it must reach across both rails and sit 3 to 6 inches above them. The first practical one is credited to Isaac Dripps, in 1833.
Corner steps (stairway)How the crew climbs aboard. Since September 30, 1979 the federal rules have required a road locomotive with corner stairways to have an uncoupling lever that can be worked safely from the bottom step as well as from the ground.
Sander (sand pipe)Drops sand on the rail in front of the powered wheels. The wheels then grip on wet rail and steep grades. The sand is kept in a sandbox and may fall by gravity or be blown down the pipe by compressed air.
Locomotive: long hood and rear end 7
Diesel engine (prime mover)The source of all the power on board. Nothing mechanical joins it to the wheels: it spins the main generator, and the electricity drives the traction motors on the axles.
Main generator (alternator)Makes the electricity for the traction motors. The diesel engine turns it. Older locomotives used a direct current generator. Newer ones use an alternator, which makes alternating current.
Exhaust stackCarries the diesel exhaust up and away. Federal rules ask for stacks tall enough, or some other means, to keep the products of combustion out of the cab.
Dynamic brake grid (resistors)A bank of resistors that turns electricity into heat. In dynamic braking the traction motors work as generators, which slows the train. They make the electricity, and large fans carry the heat away.
RadiatorCools the engine water the same way a car radiator does. Only far larger. The radiator and its fan are often set in the roof of the locomotive.
Uncoupling lever (cut lever)Lifts the locking pin so that two vehicles can part. It is worked from the side of the vehicle, so the worker does not have to go between them.
Air brake hoseJoins to the hose of the next vehicle. This makes one brake pipe the length of the train. If the train breaks in two the hoses pull apart and the brakes go on by themselves. The design goes back to the Westinghouse patent of 1869.
Locomotive: under the frame 5
Frame (underframe)The backbone of the locomotive. On a hood unit it carries the load, so the hood above it is only a cover. The federal rules call the lower horizontal support structure of a rail vehicle the underframe. The coach has one too.
Fuel tankHangs under the frame between the trucks. One 4,400 horsepower freight locomotive carries 5,000 US gallons of diesel.
Air reservoir (main reservoir)Stores the compressed air that works the brakes of the whole train. The horn blows on the same air. It is often mounted next to the fuel tank.
Traction motorAn electric motor mounted on an axle. It turns the axle through a reduction gear. Most diesel-electric locomotives have between four and six. In dynamic braking the same motors work as generators.
Journal box (axle box)Holds the bearing at the end of an axle. It passes the weight of the vehicle down to the wheels and the rails. Older ones ran on oil-bathed plain bearings. Newer ones use roller bearings.
Passenger coach 7
Door stepsBridge the height between a low platform and the car floor. On early cars with open end platforms, steps on either side were the way on and off the train.
RoofRescuers can get in through emergency roof access locations. Federal rules require at least two, a hatch or a marked weak point, on passenger cars ordered on or after April 1, 2009.
SeatsUsually a row down each side of a coach's center aisle.
VestibuleAn area at the car's end with no seating. Used in passing between the seats and a side door. Early cars had open end platforms instead. Enclosed vestibules were introduced in 1887.
Gangway connection (diaphragm)A flexible connector on the end of the car. It meets the one on the next car so that riders can walk between cars without danger of falling from the train. The federal inspection checks that each diaphragm is in place and properly aligned.
Head-end power cablesCarry electricity from the locomotive along the train. It powers lighting, heating and air conditioning. In the United States the standard supply is three-phase alternating current at 480 volts.
Suspension spring (coil spring)Soaks up shocks between the axles, the truck frame and the body. Coil springs, leaf springs and rubber air bags are the common kinds. The locomotive trucks have springs as well.
How this list was compiled: Part names and facts were checked on 2026-09-19 against three references, and a part is ringed only if at least two of them name it. (1) Title 49 of the US Code of Federal Regulations, 2025 annual edition, as published by the U.S. Government Publishing Office on govinfo.gov: Part 229, Railroad Locomotive Safety Standards, https://www.govinfo.gov/content/pkg/CFR-2025-title49-vol4/xml/CFR-2025-title49-vol4-part229.xml ; Part 231, Railroad Safety Appliance Standards, https://www.govinfo.gov/content/pkg/CFR-2025-title49-vol4/xml/CFR-2025-title49-vol4-part231.xml ; Part 238, Passenger Equipment Safety Standards, https://www.govinfo.gov/content/pkg/CFR-2025-title49-vol4/xml/CFR-2025-title49-vol4-part238.xml . (2) The Railway Technical Website (PRC Rail Consulting Ltd): Diesel Locomotives, http://www.railway-technical.com/trains/rolling-stock-index-l/diesel-locomotives/ ; Bogies, http://www.railway-technical.com/trains/rolling-stock-index-l/bogies.html ; the US-UK terminology table, http://www.railway-technical.com/glossary/us-uk-terminology.html ; and the Railway Lexicon Mk 24 of the University of Birmingham and Network Rail, http://www.railway-technical.com/glossary/rail-lexicon-mk24.pdf . (3) Wikipedia: https://en.wikipedia.org/wiki/Diesel_locomotive , https://en.wikipedia.org/wiki/Hood_unit , https://en.wikipedia.org/wiki/Cowcatcher , https://en.wikipedia.org/wiki/Janney_coupler , https://en.wikipedia.org/wiki/Bogie , https://en.wikipedia.org/wiki/List_of_railroad_truck_parts , https://en.wikipedia.org/wiki/Passenger_railroad_car , https://en.wikipedia.org/wiki/Gangway_connection and the other articles listed under sources. The wording of every label, hint and fact is our own. Licence: own work
The drawing: Drawn for this site, 2026-09-20. Own original line drawing. Looked at for accuracy only: Wikipedia articles "EMD SD40-2", "Hood unit", "Head-end power", "Vestibuled train", "Gangway connection" and "List of railroad truck parts", and the part definitions in the US federal railroad rules quoted in this dataset. Licence: own work
How it works
A diesel locomotive and one of its coaches are drawn from the side, under a small strip of the whole train. Together they carry 34 parts of a train, from the pilot at the front to the gangway connection on the coach. Find it names a part to tap. Name it lights a ring to name. Study lists all 34 names by number.
Read the full guide
Three figures, 34 parts, five groups
The top strip is the whole train, with 2 rings: the locomotive and a passenger car. The large locomotive has 23 in three groups: 8 at the front end and cab, 8 along the long hood and rear end, and 7 under the frame. The coach has 9. The group Start here: the train and its main parts holds the 10 for a first lesson on the parts of a passenger train.
How the parts work together
Nothing mechanical joins the diesel engine to the wheels. The engine turns the main generator, and the electricity drives the traction motors on the axles. In dynamic braking those motors work as generators, and their output becomes heat in the roof brake grid. Compressed air from the main reservoir works the brakes through a brake pipe, joined from vehicle to vehicle by the air brake hoses. Head-end power cables carry electricity back to the coaches for lighting and heating.
Truck means the whole swiveling wheel group, which British books call a bogie. Engine can mean the locomotive or the diesel engine inside it. In Name it, press Type it, and bogie and engine both count.
The headlight sits high on the nose. The ditch lights are the low pair, and the three lamps form a triangle.
After a round, the big button brings back the parts you missed. Print blank makes a worksheet, and Print labelled is its key.
Questions and answers
What kind of train is this?
A North American diesel passenger train. The locomotive is a diesel-electric hood unit with one cab. The coach is a single-level car with a vestibule at each end. Steam locomotives, electric trains and freight cars are not drawn.
Is a coach the same as a passenger car?
A coach is one kind of passenger car, the kind with a center aisle and rows of seats. British railways say carriage. All three names count as typed answers for ring 2.
What is the front of a train called?
The vehicle is the locomotive, often just called the engine. The sloped steel shield at its very front is the pilot, also known as the cowcatcher. Federal rules say it must reach across both rails and sit 3 to 6 inches above them.