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Advice needed, Brand New C-18 tractive effort

4459 Views 64 Replies 14 Participants Last post by  RioGrandeFan
I have one of the early delivered C-18s from Accucraft.

I have steamed it inside on my garage layout at 50F and on my newly completed outdoor layout at various temps under 40F. For each temperature and layout I have also used the same consist behind my slightly modified Ruby.
I'm a little disappointed in the C-18 compared to the Ruby. But it comes down to 2 things that can be addressed but I need advice from experienced steamers.

The first being steam, it will produce steam, and pop off. But it will run low of water if I leave the bypass open and will have to stop for a few minutes to steam up again after pumping in water again. If I close the bypass to an appropriate position to maintain water, it will barely stay above 20 psi, due to both the drag of the pump and the cool water going into the boiler. This performance was seen on treadmills too.
The first attempt to remedy this will be to check that the jet isn't plugged. I'm suspicious of this since there isn't much reaction to valve position past 1/2 turn. This is ceramic burner. I've used Butane normally and recently tried switching to isobutane. Besides cold weather gas pressure, I never saw an increase in steam from either engine. Anything else to check?

The second part of tractive effort after horsepower is traction. On the occasion that I have a full boiler, water pump in bypass, and steam to 60 psi. When I open the throttle I get lots of wheel slip with not much acceleration. With the same consist behind my Ruby, it will do a burn out, spinning the drivers as fast as it can. But the whole train accelerates at almost the same speed as a controlled start with no slip. Once it's moving about half cruising speed the wheels will grab again. I know one solution is to add weight to the engine, but it already weighs more than twice the Ruby so the weight per driver should be similar. The only other question could be the wheels, my Ruby has 2 1/2 years on it. Does that wear on the wheels give it a better grip than the brand new C-18 wheels? I am being generous with the oil on links and eccentrics and bearings, but the oil on the drivers should be no worse than the Ruby, and I try to keep the rolling surface of the tire clean.

Thanks for any advice.
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I have only ran mine on rollers so I am not sure if mine does the wheel slip thing but the video on youtube from Accucraft shows plenty of wheel slip when running it at a steam up event last summer, I just thought the rail was slippery from water and oil and needed to be cleaned off.

I do have the same issue of trying to keep the pressure up while adding water wether be hand pump or axle pump but I am convinced that I need more experience and practice firing this loco after all the only live steam loco I have ever had before this was a Ruby that is simply designed to run out of water before fuel so on that model I never worried about the water level after the initial fill.

What kind of run times are you getting? My current issue is I can't get the fire to stay lit for more than 15 minutes and after that the gas tank is empty.
I'm seeing consistent flame times around 45 to 50 minutes with the gas valve basically wide open.
All these comments seem perfectly normal for a new engine and new owners, if I can be allowed to say that, with the exception of the 15 min gas fill. Getting the tank full just takes practice and the right filler equipment. Try pressing down less, or more and be aware many fillers and tanks are different. Don't forget that those Ronson valves self-vent so you will see/hear air and a little gas venting out as you fill with liquid under pressure. When gas starts really blowing out, like when the safety valve pops, then you are full.

Traction is a whole different art form. My C-19 would easily spin its wheels when starting as it has lots of torque. Cylinder sizes have a lot to do with that, as do wheel diameters. Springing, to keep all 8 wheels on the rails, is another issue. See if you can figure out how much throttle is needed to set off with no wheel spin. :)

Wheels and the material they are made of does make a difference. The Ruby may have scrubbed the initial shine off the treads.

You are making me consider getting one. . .
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I agree with the good advice by Pete Thornton above on the gas fill and wheel spinning that will require some driving practice but as to the loss of pressure when the water pump by-pass is on, putting cold water into the boiler, is normal and usually adjusting to a higher gas setting will see that be less. I must ask have you found the right setting for the water pump by pass as on nearly all my loco's a fully closed by pass (all water to boiler) does mean too much cold water and a big pressure drop, just cracked open enough to pump some water into the boiler and the rest back to tender requires practice to get the setting right.
Also just a thought, I haven't seen one of these engines so it's a big guess, as the loco has a type of fire that requires a little draught to pull heat through the fire tubes is the smoke box fully sealed? If there are air leaks the exhaust blast will not pull much heat through the fire tubes so that while running when higher heat is needed, such as water pump putting in more cold water and a pulling a light load running slowly, the exhaust blast does not pull more heat through.
I can only speak for my alcohol fired loco's that also require a sealed smokebox to pull the fire through the boiler where any air leaks results in poor performance and when running with a light load or slow speed I always put a tiny amount of blower on to pull more heat through the boiler tubes.
I suggest a test run again with a little blower put on, only a very slight amount and see if that makes any difference, and check if smokebox seals up air tight before you light up. On a 'draughted' boiler the exhaust pipe and blower gas should hit the chimney in the centre line and be also at the right height to work properly too. I am assuming here that a ceramic burner in a firebox that requires some draught to light properly will behave like other firebox fuel sources like alcohol or coal when running. This gas burner in the firebox may not be as 'sensitive' as alcohol or coal to blast pipe/ smokebox design but I think it will have some effect.
My most enjoyable locomotives to run are these boilers that need a good front end draught and also fitted with axle pumps as it's so like driving the real thing, so when you get the hang of it it is so good to properly drive and adjust everything on the loco for speed and load.
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For me this is a big learning curve coming from a Ruby. It seems like the adjustment of the axle pump bypass will always need to be adjusted based on load being pulled, speed, fire temp and so on. I guess otherwise there would be no need for the bypass and the boiler would always stay at the appropriate level via the axle pump. I did notice when operating mine there was a time when the sight glass was reading pretty low so I stopped the locomotive and closed the bypass and hand pumped the boiler until roughly 3/4 full on the sight glass. After that pressure dropped to around 20psi but only took maybe a minute then I was back at pop off pressure. Also every time I stop to check water I burp the sight glass using the blow down this helps to get accurate readings.

Hopefully I will add RC soon and maybe its easier to monitor wheel slip using that.
Ah RioGrandeFan, it sounds like you are getting "the hang of it" now. When starting just open the regulator then close it down (not shut off just a low setting) again just as it starts, steam needs to fill the passages and cylinders so drivers start with a bit more regulator then close down as the loco moves off. That way you get enough steam to start but you avoid the wheelslip, it doesn't always work (especially if visitors watching!) If you watch video's of real drivers on 1:1 scale you will see they open the regulator and then close down to just open at starting too.
R/C is just the same as manual except you are not at the loco and can adjust constantly.
Isn't driving steam fun?
much cold water and a big pressure drop, just cracked open enough to pump some water into the boiler and the rest back to tender
My first loco with an axle pump was the AML K4, and it took me quite a while to get the hang of adjusting the bypass. As Russell says, it doesn't have to be full on or off - halfway is a setting you have to learn.

Don't forget that ceramic burners are new to Accucraft. They may not have got the process perfectly designed yet. It wouldn't be the first time that owners had to help them learn the right solution.
Your comments are exactly what I was looking for. Truthfully telling me I am lacking experience, not that I need to address a defect in the Loco. Please do not be bashful with constructive criticism with me.

The last time I ran I had accidentally left the blower cracked while running and did notice a slight improvement in maintaining pressure at low speeds. I do see a draught leak in the bottom of the smoke box where the blast pipe comes up. because I'll see the steam escape there at really low blower settings. But I think that's a requirement for drainage.

You say that your pressure is up fast after using the hand pump, mine takes a good 4 minutes.
If you could, to compare apples to apples, time how long your engine takes to pop off after initial light off. And what air temp, fuel, water level..... I'm interested in comparing the boiler efficiency in our two engines. Like I stated before I suspect a blocked jet, but want to very before disassembly.

While talking to another friend it occurred to me that my Ruby may take off with that consist, but the C-18 has the tender full of water and almost as much mass/inertia as the consist itself. So acceleration will be slow.

I still suspect the burner has something to be desired, but I'll keep playing with it a little longer before I start tinkering. But the tinkering is a fun part too.
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You say that your pressure is up fast after using the hand pump, mine takes a good 4 minutes.
If you could, to compare apples to apples, time how long your engine takes to pop off after initial light off. And what air temp, fuel, water level..... I'm interested in comparing the boiler efficiency in our two engines. Like I stated before I suspect a blocked jet, but want to very before disassembly.
It takes about 8-10 minutes to reach pop off from a cold light with 0psi in the boiler. I only try to let my might sight glass get around half full before hand pumping water into the boiler. Where is your sight glass when you hand pump? I'm thinking if yours is lower maybe around a 1/4 full its taking longer to get up to pressure since your adding more water at once. Temp anywhere from low 40s to low 50s, fuel is butane (gonna try camping gas soon) and I start with 3/4 on the sight glass.

Did you ever obtain the manual? I can email it to you if you'd like. It specifically says in bold letters "A strong fire is crucial to keep the model at pressure during running."
So our start up is similar, and I think you hit the nail, I'm running lower on the glass before I stop relying on the axel pump and hit the hand pump. Pressure is practically gone by then.

How much do you have to open the gas valve to get a "strong fire"? The last few times I've run, after the fire quits it takes almost 4 turns of the knob to close the knob.

I don't have the manual yet. I'll message you my email address if you wouldn't mind sending me a copy.
Learning and engines "balance" is part of the process on every new model. How much blower at slow speeds(if any), does the bypass just need to be cracked or opened further? How many hand pumps can you get away with and not totally kill steam pressure and how many laps of a said layout before your engine needs attention. The labor intensive nature of steam locomotives was their downfall eventually in the 1 to 1 world. And we cannot be in the cab all the time to make those tiny adjustments on the fly like the fireman and engineer do. But once you learn your engines quirks and needs, they really come alive and you get very satisfying runs out of them. Going from a Ruby(think of a VW air cooled bug) to the C18(think high end sports car) is a major learning curve. Keep running, take notes on a pad of what works, what does not. Use a stopwatch to track various metrics during the run. Once you find the sweet spot and can repeat the same great run over and over, you will have found the engine's balance. Keep in mind that colder outdoor weather will affect the gas tank pressure, so warmer water in the tender will be needed and kept warm thru the duration of a longer run. Hence why you see at steamups in colder weather, a metal tea pot on a hot plate to give the runners hot boiler/tender tank water.
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Thanks Mike,
I appreciate the reassurance that these engines are more nuanced than previously assumed. I imagine it would be a little boring if they all ran as simply as a Ruby. It explains why those that enjoy live steam tend to be tinkerers and not as satisfied by electrics. At least I'm not. I have been running room temperature water in my tender, that jug isn't insulated and does cool while sitting beside the track. I've been considering a large thermos dedicated to holding my distilled water to keep it warmer longer. Your mention of a kettle, should I be using warmer water? Say 90F as opposed to 68F that I am using now? I know that too hot of water could cause an over pressure of the gas tank. If I do run heated water, how warm is too hot in the tender?

I was able to pull the jet and ceramic burner from the Loco to inspect them. I tested them prior to doing anything on them.
Candle Gas Wood Flame Heat

Wood Yellow Table Flooring Gas

I then pulled the jet and blew butane through it backwards. After doing so the ceramic burner flame evened out more.

Wood Engineering Metalworking hand tool Gas Machine

It's a minor difference, but I believe it may have a significant impact.

Next chance I run I'll have a stopwatch to collect various metrics.

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I have one of those burners under a pot boiler Basset Lowke engine, and for it to get the best heat, you have to let the ceramic part warm up till it glows orange, then increase the fuel to it. This is where it goes into radient heat mode, otherwise your just blowing lots of mini gas jets up off the ceramic brick. This is why you need to be able to see a ceramic burner vs a poker burner. You will get the hang of it, just takes lots of practice. Same goes for alcohol fired models were you add in wick height/number of stands in each wick, or coal fired. The more complex the model, the bigger the learning curve as every single engine is different, even two of the same model and brand can have differences in how they want to be fired and ran.
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You know Mike, I remember when you joined and were "pretty green", now you are definitely getting to be an expert. It's nice to have seen your "scope" grow over the years. Just an overdue compliment.

Thanks Greg! Helps I have owned my share of different models thru the years. Still wish I could fabricate better, but for things like boilers and gas tanks, I farm out to those better at it than me.
Mike, that is excellent, I can for a fact say I haven't been patient on the heating the ceramic burner first part. And I see it in the little buddy heater I have for hunting. It really puts out the heat once the ceramic is glowing.

So I am now confident that this thread should be read more so as advice for novices when graduating to larger or more complicated locos. Thank you very much for everyone who has contributed. And thank you for any more advice that is offered.
I will try my best to get my practice in.

One piece of information I am still looking for, because if the potential dangers involved, I'm looking for guidance on how hot is too hot for tender water that touches the gas tank? Boiled water would be great for going through the axel pump without cooling the boiler too much. But I know that's too hot for the gas tank. Would something like 125F be safe? Temps that would come from a coffee pot or tea warmer?

The water in the tender is used to prevent the gas-tank from freezing, not to make it explode. Early models of the Accucraft NG/G16 Beyer-Garratt locomotive, while not using tender tank water as a supply for the boiler, were being filled with BOILING water in your southern States, where the outside temps were already in the high 80's - early 90's.

The result was that instead of being a gas, the burner jet was actually delivering a hose of liquid butane into the smokebox, where it caught fire and burned out the entire front of this $5000 model, removing paint and melting the insulation on the wheels and leaving a wreck. I guess it depends on your interpretation of the word 'warm.
lukewarm is fine, if you cannot leave your finger in the water, way too hot. Pain is at about 160 degrees F. Clearly the ambient temp is a factor as well as how fast you are using fuel.

Be careful and err on the side of less hot.

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I agree with advice above and just to add my two cents worth, for gas tank water bath, I would keep it under 70F and if the water is just warm to the touch that's enough. In really cold ambient temperature maybe add some more of the same temperature water after 20-25 minutes of running. You don't need a high temperature of water to keep your gas flowing just a tiny bit of warmth.
The gas pressure in a tank rises extremely quickly in a very steep curve to a pressure that may exceed well over 150 - 200 psi plus even when a modest heat like 85F or higher is applied so stay safe and just use lukewarm to warm water only and top up often in very cold weather. Too high a gas pressure also causes firing problems too.
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