Next to locomotive 675, everything else seems very small.

And I’m suddenly six years old again, and dearly want to sound the train horn – if I could only find it.

As it waits at the Willowbrook train yard, located just west of Toronto’s Mimico station, it’s hard not be awed by the power of one of GO’s new Tier 4 workhorses.

Even by locomotive standards, the new generation of passenger train engines are behemoths. The MotivePower built locomotives are a staggering 129,000 kilograms – that’s equal to the weight of about 71 average cars – stand an imposing 4.7 meters from rail to roof and are longer than an articulated bus.

Rail fanatics and fans have been sending our team, and one another, pictures and video as the new locomotives recently made their journey from Boise, Idaho, to Etobicoke. It’s one thing to see these sleek and shiny new engines in a social media picture or even from afar – but for me, asked to visit and describe it to you, it’s like living out a childhood dream to actually step inside one.

And I’m not alone in my excitement.

Steve Cavanaugh is Metrolinx’s senior manager of rail equipment. And he’s also what you might call a true ‘train guy’.  After spending nearly four decades in the rail industry, there’s nothing that seems to get him more excited than talking about diesel engines and raw power.

So you might say it didn’t take much persuading for Cavanaugh to let me climb aboard to see this world the way he does. Even after decades of working alongside these machines, he can’t contain his excitement around the twin 60 litre, 2700 horsepower engines. To give you an idea of just how much power that is, think of it as 36 times more muscle than the average car.

For the true train enthusiasts out there, Cavanaugh wants to make sure you know they are officially designated as MP40PHT-T4AC locomotives.

Looking out the windows of the cockpit, it immediately reminded me of what the inside of a Boeing 787 looks like. But that’s where the similarities end.

On the dashboard in front of the right seat, there’s an actual lever that controls the throttle. I placed my right hand on the control, and couldn’t help but imagine what it would actually feel like to push that lever forward and control 5,400 horsepower.

Given that I haven’t been to conductor school, that honour is actually bestowed upon the Qualified Commuter Train Operator (QCTO), better known to most people as the engineer.

The commuter train operator (CTO), which is usually called the conductor, sits in the left chair and calls out the signals and speed limits. Oddly enough, if you take a small step-down there is a cubby-cabin at the very front that houses the least luxurious toilet you could possibly imagine.

Cavanaugh tells me the real power of this beast is positioned directly behind us. Stepping through the small compartmental door of the engine bay, it feels eerily similar to walking through the belly of a navy ship.

In the fight against friction, AC is king

As Cavanaugh passes through the engine compartment, the trained engineer can give you a textbook breakdown of every hose, wire and valve.

He even gets slightly giddy talking about the alternating current (AC) drive motors and how they work. Essentially they convert electricity generated by those massive engines, into a variable frequency alternating current which powers the AC traction motors.

That matters – a lot. In traditional direct current systems used here in North America, there is significantly more wheel slippage. That prevents the locomotives from reaching their top speeds quickly – especially when under a heavy load.

The unique AC traction motors, which have been used in Europe for decades, allow the steel wheels to better bite the rail and let the trains accelerate much quicker.

“The crews immediately noticed the increase in power and pickup,” said Cavanaugh.

This is the type of design detail that he lives for. You could call him the “Godfather” of AC traction motors in North American locomotives. After literally writing a book on AC motors, his team showcased AC’s capabilities in front of railroad industry executives at Expo 86 in Vancouver.

“After our demonstration in Vancouver, Burlington Northern railway placed an order for 400 AC drive units shortly thereafter and thus AC drive in North American freight was born,” said Cavanaugh.

More than two decades later, Cavanaugh is still pioneering AC traction and GO is reaping the rewards. The new locomotives mean increased reliability, far less maintenance on the wheels and braking systems, and greater winter performance.

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After wrapping up my tour at the Willowbrook yard, I have one grievance to air. There isn’t an old fashioned chain hanging from the roof that makes the horn blare. Cavanagh explains that was done away with years ago, and the horn is now a blue button on the dashboard (For the record, I wasn’t allowed to press it – safety first!).

GO Transit now has eight Tier 4 locomotives (667, 668, 669, 671, 672, 673, 674, and 675) at the Willowbrook Maintenance Facility in various stages of commissioning.  If you keep your eyes peeled, you might even see some of them out in revenue service in the coming weeks.

The full order of 16 Tier 4 locomotives is expected to arrive by March 2019.

You can impress your fellow passengers with knowledge of the AC motors that are just one part of the mighty engines. Or, like me, you can just feel like a kid again when you hear a Tier 4 come to life nearby.