^ Here, we see a near-perfect reverser setting demonstrated for steep grade climbing when running combined steam-diesel combinations as a GP9 gives Cab Forward 4294 a helpful shove as both plow the tracks of snow during a nasty winter storm.

LOCKED REVERSER LIMITATION - First thing to know is that when running mixed steam and diesel power, anytime the throttle is not at 0% the reverser position of the steam engine IS LOCKED!! Remembering this limitation is MOST CRITICAL and means that at no time whatsoever will both your steam engine and diesel engine both be exerting their maximum pulling efforts simultaneously! Therefore, you MUST keep in mind that, depending on the running conditions, one engine is always going to be doing more work than the other! Also, if you are not mindful of this, you may discover too your steamer's boiler has gotten depressurized rapidly!



^ SP 4449 gets a helping hand from a A-B-A set of F7's for a heavy passenger haul over the Sierra Nevadas, demonstrating how most of the time your mixed steam-and-diesel locomotive setups are going to look.

STEAM ENGINES IN LEAD 99% OF THE TIME - Secondly, the vast majority of the time, you need to put your steam engine or engines IN THE FRONT, or LEAD positions, except in a couple cases with several U.S. diesels put out by DTM that I will go into detail describing Part 2, that must be put in the front position instead.

Anyway, putting the steam locomotives in the lead just makes logical and common sense because unless a scenario you are making is taking place during a period of dieselization on a particular railroad, it is most likely going to be an excursion type run to show off the steamer, or what I would call an 'excursion revenue' service of the steam engine hauling a normal revenue freight or passenger load, with a bit of diesel help, to show off just what the engine could truly pull if it is a monster goods hauling engine like the UP Challenger or Big Boy, or how FAST it was actually capable of running if it is a passenger engine like the Southern Pacific GS-4, Pennylvania Railroad K4s or the LNER Class A4.



^ In the above screenshot, the LHF SD45 is now the controlling loco so the dynamic brakes can be brought in to guide the new-build Cab Forward, #6001, to its temporary siding for boiler final tests and certification. This also demonstrates that for certain locomotives, notably many of DTM's diesels, the diesel will have to take the lead, but these are exceptions.

GRADE COMPLICATIONS AND USING THE DIESEL'S DYNAMIC BRAKES - Grades present some major operating complications when running steam and diesel together if you want to avoid having your steamer's boiler pressure dropping like a sinking stone or want to use the dynamic brakes of your diesel. When CLIMBING or ACCLERATING IN GENERAL, the controlling locomotives of the train MUST be the STEAM ENGINES!! To be brief, to make this happen, WHILE STOPPED, you must be in the cab of the steamer and start off as normal in the steamer to make it the controlling locomotive.

Now, when DESCENDING GRADES, to have access to the dynamic brakes on the diesel locomotives, and if presently the steam engines are in overall control, you MUST STOP the train and SWITCH to the cab of a diesel BEFORE you start moving again! This will make the diesel the controlling locomotive of the entire train.

This means for one thing that unless you want to only use opposite reverser/countersteam braking in a steamer along with or only use the regular brakes while decending grades, you will have to stop your train at the summit of a climb so you can move from the cab of your steam engine to the cab of a diesel and the diesel then becoming the main controlling locomotive. Only then will the diesel's dynamic brakes become accessible. Again, I will go into some more detail on this in Part 2.

As I pointed out above, in mixed-power steam-and-diesel makeups, whenever the throttle in ANY locomotive in the group is above 0%, the reverser setting in the steam locomotives is then LOCKED at whatever it was last set at until you return the throttle to 0% again. This major limitation of the reverser being locked while the throttle is at anything other than 0% is what the buik of Part 1 is devoted to and for good reason. The reason it happens is due to the game's generic coding that governs diesel locomotive behavior locking the reverser setting because of there being diesel locomotives present in the train. For diesels this is no problem at all, since the reversers for diesel locos are always at either +100% for forward or -100% for reverse, and they could care less what the precise number is, only that if it is positive, the running direction is forward, and if negative, then reverse.

But for steam locomotives, this becomes a serious problem!! For steamers, the reverser of course not only determines running direction, but also the 'cutoff' level of the cylinders and you need to be able to reduce the 'cutoff' level as you gain speed to keep from wasting steam and depressing your boiler! But if the reverser is locked after you start opening the throttle, you of course cannot do that! So now what do you do?

One thing you DO NOT DO is switch to the cab of one of your diesels while stopped and about to accelerate and try using it as the main controlling locomotive! Why? The diesel's reverser setting of +100% or -100% will also set the steamer's reverser to that level! This
WILL result in the steamer losing boiler pessure RAPIDLY as you gain speed with the diesel in control of things! Soon, the steam loco under these conditions will become nothing more than DEAD WEIGHT, becoming a major burden to the diesel or diesels!

This is where the first consideration comes into play. BEFORE you try moving your mixed steam and diesel power consist to start off and accelerate or climb with the steamer as the primary controlling locomotive, you MUST first select a 'compromise' reverser setting that will permit you to run your train at the fastest speed you plan on running for the session or scenario while satisfying the following conditions:

1) Prevents excess usage of steam that otherwise WILL result in the boiler losing pressure, YET,

2) Also permits the steam engine to contribute a significant effort to hauling the load to be hauled.

Now, from my personal experience, and I am speaking from a standpoint of knowing well how to use manual firing, I have found that for freight or goods hauling up steep grades with diesels helping your steam engine, that reverser settings according to the F4 HUD of +25% to +38% for foreward, and -25% to -38% for reverse, to be the best reverser settings to run with.

If you are using automatic fireman, your steam making capabilities will be compromised somewhat and so settings of +20% to 25% and -20% to -25% are preferable. On the other hand, if you are highly confident of your manual-firing skills and know approximately where to keep the fire mass at for whatever particular steamer you are using in your mixed-power makeup, and you also know well how to use the blower to keep boiler pressure high, then running with the reverser more closer to or at +38% or -38% will permit your steamer to be noticeably more active in helping the diesel or diesels in pulling a very heavy load.

Meanwhile, regardless of if you are using manual or automatic fireman, if you plan to be running at very high speeds on very easy grades or on flats, like pulling an express passenger train for example, +15% or -15% reverser when running with diesel assistance will permit higher speeds before loss of boiler pressure starts to become a serious issue. On the other hand, again, if the train to be hauled is a very heavy freight train or there's going be some very steep hill and mountain climbing going on, like going over Donner Pass, Stevens Pass, Cajon Pass, or running Canadian Mountain Passes, etc., with speeds rarely exceeding 40 mph, +38% or -38% reverser will allow your steamer to give your diesels the serious helping hand they'll need in maintaing speed.

The major downside of using these reverser settings is that at speeds under 10-15 mph, the diesel locos will be doing the vast majority of the work. It will not be until the train is moving much above 10-15 mph that your steam engine or engines will start to make a serious difference in pulling effort. The steamers will more serve to keep the train moving at a healthy or even very fast clip once the diesels have gotten things rolling, and as speeds pick up, the steamers will be doing more and more of the work.

It is possible to use reverser settings greater than +38% or -38%, but the only times I can recommend this is if you are going to be crawling along a brutal grade with an extreme load with your mixed power at around 10-15 mph, and even then +/-50% to +/-60% is as high as I would take it if if you want to give your steamer a fighting chance of not running out of breath and pressure.

The last thing, is that by completely closing the throttle briefly, snapping it closed using the mouse, it is possible to change reverser settings at speed and then quickly move the throttle back open again using the mouse. However, the ONLY time I can recommend doing this is while you are running on a flat or gentle slope and are NOT on a severe grade! Doing this on a grade with a heavy load WILL cause you to start losing speed irrecoverably from the brief complete interruptions of pulling effort from all your locomotives, steam and diesel combined. If you need to change reverser setting on a grade because of your speed becoming too high, it is better to reduce throttle and slow back down instead and wait until you are on a flat section of track before closing the throttle completely to change reverser setting.