Real Life Steam Double Heading

Uht Oh!!!  You said "Real Life" and "Lash-up".  The "real" and "scale" folks are going to hammer you now.  I wonder who will be first?

I will be first…

There is no such thing as a steam locomotive “lashup.” It is a doubleheader. Yikes.

You don’t “speed match” when running a locomotive (any locomotive) in a doubleheader. Each locomotive pulls on the train with whatever power setting is applied by the engineer. The two engines may not be pulling with equal power, but both are adding their power to the effort of pulling the train.

The throttle in a locomotive (steam or diesel) is not a “speed” control. It is a power control. When running NKP 765, I’ve had the throttle wide open at 3 mph, and also at 79 mph. Same for running a diesel. Starting out, you might have the throttle in Run 8 (wide open) to accelerate, or climbing a grade at 10 mph, and you could also have that throttle in Run 8 at 79 mph.

Well,,,,,,,,,,,,can we tar & feather the original poster and run him out of town?

@Ron045 posted:

Uht Oh!!!  You said "Real Life" and "Lash-up".  The "real" and "scale" folks are going to hammer you now.  I wonder who will be first?

Ohh boy haha

@Rich Melvin posted:

I will be first…

Noted! I didn't actually know there was a difference in a lash-up vs double heading. I don't actually know where I picked up these phrases. I'll remember double heading. I definitely feel like I should have realized the speed vs power control given the way locomotives work. Off topic but serious question, but do you turn up the power or the amperage in an electric locomotive?

Anyway, back on topic! That's interesting! I would not have expected that to be the case. I would have expected there to be some sort of communication between engineers to get the efforts close.

@Hot Water posted:

Well,,,,,,,,,,,,can we tar & feather the original poster and run him out of town?

Catch me if you can!!

@BillYo414 posted:

Off topic but serious question, but do you turn up the power or the amperage in an electric locomotive?

Increasing the Voltage increases the power.  Ohms law comes into play here: Voltage = Current (in Amps) times Resistance or Reactance.  Watts Law: Power in Watts = Volts times Amps (current)

The throttle in a diesel locomotive has nine positions, idle, plus Run 1 through Run 8. Changing the throttle position changes the power output of the locomotive. Internally, the governor sets the rotational speed of the Diesel engine based on the throttle position, and the electrical control circuits control the voltage sent to the traction motors. The current drawn by the traction motors can be 1,000 amps or more at low speeds.

An electric locomotive functions in a similar fashion. The throttle controls the power, while internal circuits determine how much voltage to send to the traction motors to develop the commanded power setting,  thus controlling the power output of the locomotive.

Related to this topic, I must put in a plug for Rich's video on steam versus diesel power for any who have missed it.

https://ogrforum.ogaugerr.com/...vs-diesel-horsepower

@BillYo414 posted:

Ohh boy haha

Noted! I didn't actually know there was a difference in a lash-up vs double heading. I don't actually know where I picked up these phrases.

The term "lash-up" is a toy train/hobbyist term apparently started by Lionel. In the real railroad word, the term "lash-up" is not used. Steam locomotives are double headed, while diesels or electrics are MU'ed together into an "MU consist".  

I'll remember double heading. I definitely feel like I should have realized the speed vs power control given the way locomotives work. Off topic but serious question, but do you turn up the power or the amperage in an electric locomotive?

Advance the throttle.

Anyway, back on topic! That's interesting! I would not have expected that to be the case. I would have expected there to be some sort of communication between engineers to get the efforts close.

Remember, back in the days of regular steam, the engine crews, i.e. Engineers and Firemen plus Conductors and Brakemen, were all very, VERY familiar with their operating territory (they ran over the same tracks, day in and day out), thus they KNEW what to do and when to do it.

Rich,

Since the original post was curious about "matching" double headers, share with him the way two steam locomotives start off together.  I'll bet most  folks would like to know how your do it.  I've worked with crews on double and triple headers and have seen it done well and not so well.   

Earl

I too would like the questioned answered.

@Conductor Earl posted:

Since the original post was curious about "matching" double headers, share with him the way two steam locomotives start off together.  I'll bet most  folks would like to know how your do it.

The engineers open their throttles and the train starts to move. It is really that simple.

There is no “magic” to this. Recall what I said about the throttle being a POWER control, not a SPEED control. If one engineer opens his throttle and the other doesn’t, it’s no big deal. Both engines are going to move regardless. In some situations, the train might be started with only one engine working, in order to save a little fuel. The second engineer would open his throttle to add the power of his locomotive to the train to help only when needed.

Care must be taken stretching the slack in the train, just as an engineer would do in every start, but it is not all that different than starting a train with a single locomotive.

@Ron H posted:

I too would like the questioned answered.

Which "questioned" are you asking about?

I assumed it was the question about starting a train with two engines.

@SteveH posted:

Increasing the Voltage increases the power.  Ohms law comes into play here: Voltage = Current (in Amps) times Resistance or Reactance.  Watts Law: Power in Watts = Volts times Amps (current)

I'm electrically challenged, to be honest. The electrical engineers I have worked with said it's a common symptom of being a mechanical engineer But I just wasn't sure if amps or volts are advanced to increase the speed. I know watts are power. I see below that voltage is increased. I'm sure this seems as simple as the sky being blue to some but it's interesting to me because it's not my strong point. I appreciate the explanation!

@hokie71 that was an awesome video!

@Hot Water Does MU mean multiple units?

My original question was just about how steam engines matched speed when double heading at any point; start, going, stopping. I assumed diesels/electric locomotives were controlled in groups by electricity (stop me there if I'm wrong!) but steamers are ran by people. So I was wondering how they managed not to fight each other. Pooling the power is a simple enough explanation for me. Especially if you have engineers that are familiar with their machine and their route. 

I would have just thought it would be hard on parts to be pushing and pulling one another if speeds are not kept consistent. I thought maybe there was a trick they used to signal to one another what they're doing.

I am very happy with the outcome of my original question though! I was looking to learn one thing but I learned a heck of a lot more. Now I can harass people that come over and run trains

You cannot advance amps. A piece of electrical equipment only draws the number of amps it needs to work. You could connect a 12-volt battery capable of delivering 1,000 amps to a 12-volt light bulb, and all that will happen is that the bulb will light up.

You increase amps by increasing the voltage. The increased voltage will cause the equipment being powered to draw more amps and develop more power…more watts.

MU = Multiple Unit

Excellent! I appreciate it! Especially the electrical end of things.

It might help the OP to know that, unlike our model electric trains with worm gearing,  real locomotives can roll freely.  So that is why in real life one locomotive can pull the other as explained earlier.

@John Sethian posted:

It might help the OP to know that, unlike our model electric trains with worm gearing,  real locomotives can roll freely.  So that is why in real life one locomotive can pull the other as explained earlier.

Steam locomotives have "neutral"? For the sake of a lengthy write up, no need to get into the depths of the plumbing (the pipefitting?). A yes or no is fine. I'll look it up on my own.

That does help though! I was unaware. I thought the pistons in the cylinders would have caused some issues with compressing the air in them unless opening the valve to drain them (the blowdown valve?) allows enough air in and out to stop the compression. Having the ability to roll freely explains a lot haha