Diesel locomotive, Rolly Martin Country

CP Rail's faithful workhorse and how it works:

The most common locomotive on the system in 1977 was the General Motors, Electro-Motive Division, SD40-2. CP Rail had around 400 of them in 1982 and most of those were still around 20 years later. Railway stuff is built to last, eh?

SD40-2 Locomotives:

Top speed: 65 mph
Weight: about 200 tons
Horsepower: 3000 hp

So they don't mix them up, railways put big numbers on their locomotives. CN and CP traditionally use 4 digit numbers.

There is also a pronunciation tradition: two groups of two digits.
Locomotive 1234 would be referred to as "the twelve thirty-four".

Once there was a story about a police officer asking for the make and model a locomotive involved in a level crossing accident. Legally, it pays to be specific. However, some rail enthusiasts think this story is pretty funny because they know that just four digits nails down the identity of a specific locomotive for 30 years or so.

Here is a picture of some "SDs":

CP Rail SD40-2 locomotive consist at Field

The lead locomotive is "the 6018". This picture was taken at Field, B.C., in 1984 as this eastbound train prepared to climb over the Continental Divide of the Rocky Mountains.

The engineer and the headend trainman are in the cab of the 6018. Behind them is a 3000 hp diesel motor and some pipes and wires and stuff. The big black tank underneath, close to the rails, is full of diesel fuel.

So, how do you get all that power to those 12 wheels?

Hint: There is no automatic shifter with "park, reverse, drive" on it.
And if the 6018 had a manual transmission, can you imagine the size of the clutch pedal?

All 3000 horsepower gets to the wheels through WIRES. Wire is cheap and effective.

Between those twelve wheels are six axles. And geared to those axles are honking big electric motors.

So some snooty people would probably tell you this is a "diesel-E-LEC-TRIC" locomotive. And it works like this:

Diesel fuel is pumped from the tank to the motor (somewhere in the red part of the locomotive).
The motor is attached to a big electric generator.
The engineer moves an electric switch to position 1, and the main generator starts "loading".
Electricity flows to the big electric motors at the axles and we're moving!
Once the train is moving, the engineer has a total of 8 throttle positions which can be used (in forward or reverse).

Here is a diagram to make things a little clearer:

Diesel locomotive: traction motors, diesel motor powering generator

Did you notice in the photo above? Two of the locomotives are pointing backwards!

No problem, just connect them up properly and they know enough to run "backwards".

Railways like doing things economically - that's why diesels replaced steam engines.
Four steam engines would require 4 engineers (and 4 firemen to boil water).

One person at the throttle controls everything in our picture.
Air hoses and wires connect the locomotives so they all act as one.
Just think of it as 800 tons of plug'n'play equipment.

Below, in the 1990s this SD40-2 is slowly leading a grain train through switches at the east end of Thunder Bay. Through the window, you can see the engineer at the controls. A trainman is visible through the window behind him on the left side of the cab. It is probably the conductor with the red hat riding the pilot of the locomotive. With 9000 horsepower, the crew will be mixing and matching groups of 100 ton grain cars for recreation.

CP Rail SD40-2 cab before switching at Thunder Bay

If you are ever in the market for 3000 horsepower diesel locomotives, here is some advice:

For light work, and for trains which need to accelerate quickly and run fast, choose 4 axle locomotives.
For long heavy trains which climb hills, run around many curves and can't always run fast, choose 6 axle locomotives like the CPR has done for most of their equipment. Six axle locomotives are better at pulling hard at low speed for a long periods of time. The electric traction motors do not get overworked and the extra wheels give the locomotive better traction on the smooth steel rail.

Here's an illustration:

CP Rail SD40-2 locomotive consist pulling freight at Field Hill

These three SD40-2s are leaving the slow terminal track of Field, B.C. after a crew change on this August morning in 1990. The engineer has just opened up the throttle and the diesel motors are smoking as they spin the generators faster and faster to produce more electricity. The electric traction motors will be warming up as they strain to accelerate 7000 tons up the hill. This train will be heading up through the Kicking Horse Pass to the Continental Divide in the Rocky Mountains - 13 miles of constant hard pulling.

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