Would there need to be a fireman's unit?

The fireman has to maintain boiler pressure, or the paired engineer's unit sends a signal to the engine to stop the engine.

There would be gauges for fuel and water amounts that deplete as the engine runs, and need to be "refilled"  at a servicing station.

I think MR had something like it in one of their April Fool's issues. 

Neil's Steam Throttle

@ Joe, see Neil Erikson's steam throttle on the first post on page 52 of the Realistic Handheld Diesel Control Stand Throttle thread.  He also has a drawing of a steam throttle and lots of great ideas.

https://forum.mrhmag.com/post/realistic-handheld-diesel-control-stand-throttle-12203251 

I'm expecting him to chime in soon.

A simple solution might just

A simple solution might just have a water gauge that drops based on load and speed. Generally coal will last the entire run but water might not. Adjustments to the coal and water feed might be needed to keep steam presure at the level needed. So a throttle, a brake, coal and water and a switch for retainers might be very useful.

Backhead

Years ago (like 20+) RMC had a cover story on someone who had built a full backhead using live steam components and set it up as a controller.

That was pre-DCC so he was trying to use current draw to measure how much "water" was consumed. I don't recall all the details and the mags are in storage. Not exactly a walk-around controller, but I'd buy one.

I do remember someone suggesting (in a follow-up letter?) that if the water got too low then a flashbulb should go off in the engineer's face!

Bob

Look and Arrangement

Simulating the look and feel of iron steam locomotive levers would, I think, be the hardest challenge.  My initial thoughts would be to have a horizontal throttle lever in about the same location as the present diesel throttle.  Perhaps an open metal quadrant (an arc) protruding from the case could be done.  The Johnson bar, also with a quadrant (arc), would be in a vertical arrangement to the far right side of the box.  The horizontal brake handle below near the bottom.  Could an exposed cylinder of sorts be put below it to simulate a brake valve?

Most steamers I've seen have the light controls over the cab window or a similar place, making that difficult to realistically place on the throttle box.  I think I would just put the light switches in the inside of the "U" shaped area created by the three levers.

The whistle would be harder.  I have seen a few steamers though that had a metal lever that had the whistle cord attached to it (with somewhat of a bell-crank look to the assembly).  If a metal lever stuck out where the present diesel horn lever is, that might be sufficient.

I'm not so concerned about things like the water glass or steam pressure gauge (there's no ammeter or air pressure gauges on the diesel controller and I'm not seeing a large complaint about that).  Perhaps the gauge features could be somewhat simulated and appear on the screen readout if selected from the menu.

Of course, the look of all surfaces and levers would have to be that of metal (no plastic handles).

Backhead model in RMC

That was non other than Jack Burgess, one of our Getting Real columnists. I've been to Jack's layout on several occasions, and I've seen that backhead model. Maybe we can get Jack to do a retrospective on it and blue sky how he might redo it with DCC.

Operation?

Diesels are pretty straight forward (although I wonder if the controls let you work the brake and the throttle at the same time?)

I wonder how many people even know how the controls of a steam engine work?

What Dave Husman said.

I had to bone up on this to know what Joe was referring to vis-a-vis Johnson bars. I knew you used it to reverse and that was all I knew.

Checking out some of the images of backheads on the internet reveals that they range from pretty simple to a level of complexity that would intimidate an airline pilot. What to include?

Keeping in mind my limited knowledge, I thought a sort of modified NCE or MRC throttle shape might serve as a starting point for a hand held, kinda backhead looking steam throttle:

I found myself wanting to include more and more of the standard throttle features, to the point that it would look and function pretty much like my NCE Powercab, only with a rounded top. How do I select a loco; how do I recall a loco? 

I am way out of my depth as to how one would implement programming and CV manipulation on such a creature. 

There is a lot that I might learn here if this subject takes flight.

David Stewart

Comments?

Thanks Dave;

Here is the image:

There needs to be an injector!

Steam Locomotive Controls

Creating a hand held throttle to simulate steam locomotive controls might be a pretty tall order. The reversing lever or Johnson Bar on a steam locomotive is not just forward or reverse, it has many notches and is almost like a transmission. When running a steam locomotive you have to balance the position of the reversing lever or Johnson Bar with the setting of the throttle to maintain your speed for the track section you're operating over. I'm not sure this can even be accomplished in DCC?? From what I've been told, engineers on steam locomotives made more adjustments to the Johnson Bar setting than the throttle setting, which is completely opposite of running a diesel locomotive today. 

Highly Variable

From what I have seen of steam back heads they are all different! Basing it on the existing proto throttle I would move the throttle lever to be vertical and on the left side, the reverser/johnson bar would be a similar lever but on the right hand side, it would need to be continuously variable with neutral in the centre, reverse downwards and forward up. The brake could remain as it is on the existing proto throttle. You could have gauges represented on the LCD screen, water level and steam pressure. I would round the top of the throttle, paint it black with some rivets along the edges. 

The difficulty is in how to translate the throttle and reverser positions into movement. I have never operated a steam locomotive so some help from those who have would be in order! My understanding is that to get a train moving, especially a heavy one, you would give it lots of throttle and move the reverser to its maximum, then as soon as the train starts to move you would pull back on the reverser increasing the cut-off, you may or may not reduce the throttle at the same time. Once moving along, you would reduce the throttle and increase the cut-off to minimize the amount of steam used. So it is the combination of the throttle and cut-off that determines the power.

Unlike the usual model throttles with knobs that control the speed, you actually control the power, maximum power is with the throttle wide open and a minimum of cut-off, once up to speed you might have the throttle at a low setting with the reverser near to the neutral position. You could be going 60 mph with that arrangement, the positions do not translate directly to a speed rather it is the amount of power applied over a period of time that gives you speed. Going uphill with a heavy train you could be max'ed out on the throttle and cut-off and still be only going 10 mph. That is actually the same with diesels, the throttle position does not correspond to a speed rather the power or force being applied. There would have to be some sort of algorithm applied to the throttle and reverser positions, integrated over time, to determine the speed step that the throttle should send out.

You could do something fancy like calculate the amount of steam being used based on the throttle and cut-off positions and cause the steam pressure to drop if you are using too much, eventually bringing everything to a stop when you run out of steam! With a steam engine you have a limited boiler capacity dependant on the size of boiler and firebox grate size and the type of fuel being burned. Maybe we could have settings for a wood burner (low steam capacity), hand fired, stoker fired or oil fired, if you aren't careful with how you run, you could quickly use up all the steam and come to a halt on a hill! As the steam pressure drops you would slow down even if the throttle was at its max.

You could also calculate the water used and when it gets low, signal an alert requiring you to stop for water!

would there be constant acceleration?

ignoring the other interesting aspects of a steam locomotive

... i tried asking about acceleration on a diesel locomotive and walked away with the impression that the electronics of the engine optimized the force/horsepower to maximize engine performance to obtain a speed/horsepower setting dictated by the throttle step (horsepower is a function of speed) -- acceleration is controlled by the electronics.  (why would you want to take longer than necessary to get a train up to speed)?

and this behavior is consistent with how DCC momentum works, speed increases at a constant rate dictated by the momentum setting and the maximum speed is dictated by the DCC speed setting

i assume that on a steam engine, the throttle controls the amount of steam feeding the cylinders.   The engineer modulates the throttle to keep the wheels from spinning and accelerate the train to the desired speed

i assume that the acceleration depends on the weight of the train and the amount of steam feeding the cylinder -- acceleration need not be constant (deceleration depends on how hard you hit the brakes).

i'd like to see a DCC controller where acceleration can depend on the throttle setting as well as a "mass" instead of a momentum DCC setting.    The acceleration would depend on the difference between the current speed and throttle setting (like a car)

As a steam-only guy...

...I had given this some thought for a while.

The problem that I see with all of the potential hand-hold steam throttles is... How can you manipulate all of those miniature buttons and levers while wearing those heavy leather gloves?

@Neil

Neil, I’m curious as to how the 5 position johnson bar works since decoders only have forward and reverse. I understand you could put a neutral in it but what do the other two poles do?

Too many variables?

Generally, one diesel operates the same as another in regard to the controls. It's a big diesel engine with a large tank, running traction motors. A steam engine is totally different in regard to many aspects. Size of the loco, tender capacity, fuel type (coal v/s oil), etc. This doesn't lend itself to a 'one size fits all' concept for a throttle like the ProtoThrottle did. You also had a bunch of knobs to turn to run one, and you can't really do that on a small throttle and not have them break over time.

There's also the size issue. The controls for a real steam locomotive are over a large area and are of course meant for two people. You can't really do that justice with a hand-held throttle for one person.

I'd say, just go with a standard DCC throttle but with rivet heads embossed all over the face. Make the reverser one lever to the left, the throttle a sliding bar (with a brass tip to look like a real one) to the right, and a gauge looking like a water sight glass to the upper left showing current. I wouldn't make it dependent on it like a real water glass, as tat varies wildly from loco to loco as some could run for a long time between water stops.

WiThrottle Implementation

It sounds to me that this is a great opportunity for a "realistic" WiThrottle implementation on iPhones.  All the logic for the different types of steam locomotives would be handled in software, and the controls specific to the locomotive presented in the WiThrottle interface.  You could link a specific throttle with a specific locomotive.

I find the WiThrottle interface fun and easy to use.  On one layout I operate, many of the older throttles have broken and the owner has installed the Digitrax WiFi.  Now we just use our phones and it saves a lot of money on throttle replacement.  So, a prototypical throttle could reach a lot more people.

Steam Locomotives vs. Diesel Electric Locomotives

Greg,  On diesel electric locomotives the control systems monitor wheel slip and correct for wheel slip i.e. reduce current to the traction motors, sand or a combination of both. On older locomotives, the higher the throttle notch the greater the engine RPM which created more voltage and current from the Alternator or Generator depending on the locomotive. Older 6 axle locomotives also used series parallel and parallel contactors to control how the voltage and current were applied to the traction motors. New locomotives use gated diodes in the alternator to control the alternator output along with sanding to control adhesion.

On a steam locomotive you can control acceleration by both using the throttle and the reversing lever / Johnson Bar. You can push the Johnson Bar all the way forward, open the throttle to get the train moving and as the train begins to accelerate pull the Johnson Bar back toward the center position to increase the engine speed, without having to use more steam. Of course operations in a mountainous terrain will be completely different than those of a water level route. A good engineer in the steam days knew how to balance the position of the Johnson Bar and throttle to get the train over the road at timetable speed without constantly using up all his steam pressure. It's not a simple process like on a diesel electric and in that respect a prototype hand held steam throttle will be more complex than the hand held diesel electric throttle.

Then you add in all the sub-systems of keeping the fire hot, maintaining steam pressure, maintaining the right amount of water in the boiler, keeping track of fuel and water in the tender and you can end up with a very complex hand held throttle.

I guess the real question is, just how real does everyone want to get? and how much would everyone be willing to pay for such a throttle?

Johnson Bar

@Tim:

I used a five position guitar switch to allow a center position, two forward and two reverse. Brent has it right in that the more forward the bar, or reverser lever, is placed then the faster the steam is used. More steam in the cylinders equals more power but used for too long it would deplete the amount a available. Many more positions would be preferable but this was simply a way to get started with the programming logic. 

@Michael - ouch. The entire idea of this or the LrotoThrottle is to provide an option for a more realistic tactile controller. Watch Bruce Kingsley’s videos that started all this and imagine the same experience in a steam engine. Yes, engine blackheads were very different but the same basic functions were used regardless of size or make. 

Throttle - preferably a push / pull rod 

Johnson Bar - notched reverser lever that allows variable abount of steam to enter the cylinders;

Brake - ideally a train as well as independent engine brake;

Bell & Playable Whistle;

Water level & Steam Pressure gauges with filler valve (usually blvalves were also used to check water leve in the boiler as well) - water stops would be sections of track that recharge a battery or capacitor. Running water below the crown sheet would result in a sound effect and engine stop;

Steam generator for lights;

On the wish list is a decoder in every freight car that would be consisted with the engine similar to the SoundCar by Soundtraxx. It would relay loaded or empty data to affect inertia or momentum as well as read / write destination i.e. a digital wieghbill or tab on car. 

It would be cool to simulate wheel slip and sand application as well!

Virtual Steam Engine

Go here and put Trainz 2009 on your computer and drive a steam engine.

http://ts2009.trainzportal.com/free/

The setup of model steam doesn't have the physics or the control for a proper throttle.

Harold

would steam locomotive behavior be properly modeled?

for example, applying too much throttle when stopped should not cause a jack-rabbit start.   It should result in little speed increase (little traction) until the throttle is reduced and traction regained.

similarly, any sound should be of wheels slipping.  unfortunately, the wheels on the model do not spin

would chuffs sound different depending on johnson bar position and throttle?

seems that a more ideal decoder would receive johnson bar setting as well as throttle setting in order to properly simulate the behavior of a steam locomotive both in terms of speed and sounds.  (i assume momentum/mass setting specifies the weight of the train -- # cars).

could a DCC function command be used to increment/decrement a johnson bar position?

Steam behavior

True, you could list a lot of stuff that a seam engine would (or wouldn't) do that simply cannot be duplicated in model form. You sure couldn't model poor firing (you know, the stuff that makes those black clouds that train fans love but firemen and management hated), keeping water over the crown sheet on different grade types, adhesion, or really even how a throttle acts on a steam locomotive.

For example, I've driven antique and modern cars, had stick and throttle time on old prop and modern jet aircraft, and even have had throttle time on steam and diesel over the years. They each react totally different, and none are a matter of "Make thing go now" with no differences. Each respond differently by type. Some react to throttle instantly, some are delayed and some have to be coaxed (even when working as designed). My modern SUV reacts totally different when I stomp on the gas than my 1944 Willys Jeep does.

An old SP hogger I used to live down the street from said it best. He said that diesels were a machine, pure and simple. It idled and when you needed it, you just hit the levers and off it went. Steam, he said, was like an animal. You had to know how each specific locomotive ran and you had to be aware of it every moment, unlike the diesels that came later. The gauges and levers and such on steam were some of the tools to get it to move, but in the end, it was the grey matter of the hogger and fireman who got it running and you just didn't push a button. Having ran both, I got his point (as would, I'm sure, anyone who's done both, or even just ridden the cab of each).

My point? You can't hope to simulate steam and all it's wily ways, not with a simple throttle, anyway. My layout is mostly steam (and all steam in op sessions) and I've long since accepted that it's as good of a simulation in (small) 3D as I can get.

steam vs steam

i believe your point is that, for example, two Reading T1s have their own personalities.     a 4-8-4 will not only have different characteristics than other 4-8-4s of the same type, but difference between 4-8-4s from different railroad,  and significant difference between a 2-8-0, 4-6-2 or  0-6-0

but with today's decoders, is there a difference in behavior between two locomotives having the same type of electric motor, weight and gearing?   does it matter if it has a steam or diesel shell

i am suggesting that steam vs diesel characteristics need to be implemented in the decoder.   Since each locomotive has it's own personality, this personality would be easier to capture and implement in the decoder than in the controller

while i think steam characteristics can be implemented in a DCC controller, any model controlled by that throttle would have the same characteristics: 4-8-4, 0-6-0 or a diesel

maybe a steam proto throttle can have multiple personalities that can be programmed and saved and selected when the loco is selected. 

i think a simple characteristic is the maximum speed and horsepower vs current speed.   i believe johnson bar setting determines horsepower, hence acceleration, but needs to be adjusted as speed increases.   Increasing the throttle with an improper johnson bar setting should not result in as much acceleration as the proper john bar setting.   adjusting the johnson  bar may increase speed.   I believe this can easily be emulated with parameters programmed into a decoder driving an electric motor driven model.

One step at a time?

First thing missing is a Johnson bar. The throttle is de rigueur.

As I see it, the throttle equates to steam. The Johnson bar equates to cutoff: that is, the amount of steam being used per cycle of the steam pistons.

So speed steps essentially equate to steam. Yes? No? 

But what equates to decoder capability equates to cutoff?

On my NCE Powercab, running Soundtraxx decoders, I've found I can simulate the sound of a hard start-up (with the DDE working) and settle into a nice quiet (not wasting steam) sound by punching the Inc Fast (increase fast) button a couple of times and then using the thumb wheel to reduce the speed steps down to the running speed I want. I am trying to arrive at the running speed (going down) at the same time that the locomotive (going up) arrives at that speed. So I'm kind of faking finding the "company setting" on the Johnson bar.

On hills the DDE automatically kicks in extra chuff (or less, downhill). 

So is it the DDE settings that equate to the cutoff function of the Johnson Bar? Or something else.

My point is not that I am even remotely on the right track here, but that, as the OP noted, we need to identify which CV's equate to what and then evaluate whether or not they can be made to play with each other. 

Which CV's equate to steam and which to cutoff?

Step one.

David Stewart

CVs

none.   CVs store values that don't change (constants) that capture desired behavior (e.g. max voltage, momentum)

steam is the throttle (the DCC controller speed setting).  cutoff would also need to be controlled from the controller.   I suggested a function button, similar to F6 that controls braking on some decoders.   (is the DCC command set designed for steam)?

but CVs would be needed to capture the "personality" as well as capabilities of the locomotive (e.g. 4-8-4 vs 0-6-0)

yes, i'm suggesting a new type of decoder that would make a proto-steam throttle more realistic.