Trains and trams come to life at the Siemens Mobility factory

There's not much to see from the road, or even the parking lot. But it's fascinating inside.

For more about our tour, check out Where trains are born: Touring the Siemens Mobility factory. 

As with most big things, the trains all start with little things. In this case, it's pieces of metal welded together.

Siemens contracts out the manufacture of the basic pieces to local companies, then it assembles them on site.

The transparent red dividers block much of the intense blue-white light from the welding. 

A welder welding some welds.

The body will rest on top; four wheels go below.

Not only are all of the parts made to precise tolerances, there are multiple testing stations for quality control. This machine simulates the weight of the train body. 

Stainless steel is hard to work with, but it's used for train car bodies because of its strength and longevity. It's also ideal for many other types of vehicles, including SpaceX's Starship.

The walls, floor and roof of a car are assembled separately and then joined together. This is part of a roof, with an open space that will eventually hold air conditioning equipment.

The inside of one of the walls is bare before it's joined with other parts.

This is one of the Venture trainsets used on intercity routes, like with Brightline/Virgin Trains USA in Florida.

Like all modern cars, and unlike most older trains in the US, the Venture cars have crumple zones at each end, or crash energy management as Siemens calls it. These are designed to absorb energy in a crash, protecting passengers from some of the impact.

In addition to seats, there will be an ADA-compliant bathroom. Under the floor will be the electrical equipment and a compressed air container for the braking system. The windows are larger than what you'd find on older Amtrak trains.

Note the elaborate air conditioning ducts, which should help keep the car cool, without the air blowing in your face like it does from an overhead nozzle on an airplane.

To make it easier for the workers to get under the cars, they're positioned high off the ground on these strange-looking bogies with stilts.

The next building over is where Siemens builds the Charger locomotives. This is the underside when viewed from the front.

A car comes together, piece by piece.

This seems like a lot of space, but in a few slides you'll see it packed full of a 4,400-horsepower V-16 engine, radiators, electrical generators and more.

This is the massive fuel tank, which sits under the engine. It gives the Charger a roughly 1,000-mile range between approximately 2,000-gallon (7,500 liter) fill-ups.

More Ventures in various stages of completion sit outside. 

In the fore- and mid-ground is Siemens's test track, which has AC and DC power lines. In the background rumbling past is a long Union Pacific freight train. I didn't catch the number, but I'd like to think it was pulled by the same 7419 GE Evolution locomotive I saw when I took the Coast Starlight 39 hours from LA to Seattle.

Another under view of a Charger. At 71.5 feet (21.79 meters), they're quite long.

In addition to train cars and locomotives, Siemens also builds trams, which are part of the transit systems in 17 cities in across the US.

Though brand new, this tram for Denver's RTD looks exactly like the cars that went into service in the Mile High City in the '90s.  

You may have been wondering, as I was at this point, how Siemens transports vehicles around the factory. (There aren't rails everywhere in the facility.) Here's the answer: Essentially, a highly agile powered dolly can hold an entire car or locomotive.

Here a Charger is getting loaded onto the transport, though it's only moving one bay down for painting.

The wheels will pivot and move the transport horizontally. It also can rotate on its axis.

This can only be the sandblasting bay. The sand gets reused.

Down in the paint shop, trams are getting a few coats.

Given the amount and variety of wiring, it's far easier to lay it all out on tables to make sure everything is where it's supposed to be and connected in the right places to the right things.

The frame of an S200 tram takes shape.

Here's where a Charger finally becomes a Charger.

The Cummins turbocharged 95L V-16 engine produces 4,400 horsepower, but that's not what directly moves the train. Instead, it's a diesel-electric, where the engine is connected to a generator, which in turn powers electric motors that drive the wheels.

This is the generator, mounted on the front of the engine. 

This room will house all the brains of the locomotive in modules that can be replaced relatively easily if something goes wrong.

The cab minus of any trim or controls is far from comfortable. For how a Charger looks in its fully completed form, check out Charger into the future: Inside Amtrak's new 4,400 hp locomotive.

In addition to Amtrak, Siemens is building Chargers for Maryland's MARC commuter rain, Via Rail Canada, and others.

The top speed of the Charger is 125 mph, or 201 km/h. In normal use, tough, it will be far slower due to the quality of the privately owned tracks in the US that most intercity trains use.

Here's a view you're not likely to see, hopefully. The box on the mid-right is the electric traction motor.

The console in the cab of a Charger that destined for the nearby Altamont Corridor Express, which runs between California's Central Valley and the Bay Area. 

The emissions equipment is above the engine. Siemens claims 90 percent better emissions on the Charger compared to older locomotives in wide use, plus 16% better fuel economy.

On both sides of this section, which is screened-off but open to outside, are massive radiators to help keep the engine cool.

At the back of the locomotive is a room with blowers that keep the rear traction motors cool and equipment that takes the DC power from the generator and converts it to AC to drive the motors.

This was one of the few buildings where I could get an overview. Below, S70 trams get their final kitting out, already painted in their various liveries.

Siemens has built over 300 S70 trams for eight city metro systems across the US, including San Diego, Houston, Charlotte, Atlanta, Salt Lake City and others.  

A trio of S70s, the middle and right ones are headed for Sound Transit in Seattle.

Four of the standard six axles are driven for a top speed of 65 mph (105 km/h), though that varies depending on specific metro system. Usually it's a three-cabin design, with two mirror-image end cars, and a smaller central car, with around 60 to 70 seats total.

So ends our tour, with one end of this tram. 

For more about the trains and trams you've seen, and about our tour of the factory in general, check out Where trains are born: Touring the Siemens Mobility factory.