There is no rule that I am aware of but 2% is generally considered reasonable for most situations, so to get 4" of rise you would need about 16' of run. That works out to 1/4" per foot, or a 1/2" block on the end of a 2' level, then you just adjust the grade till the level is level. If you want more or less grade you adjust the thickness of the block to suit. One thing to consider, if your grade is too steep your engines will be able to pull fewer cars up the grade, till the engine can't even get itself up the grade.

 

For real railroads, 2.2% was established as a standard max ruling grade based on the B&O. There are some that are steeper, but many are very close to 2.2%. You can probably go a bit more than that with model trains if you don’t have the room. I used a max of around 3% on my O gauge layout. When determining how long of a run you need, don’t forget that you need a gradual transition from level to your max grade at the top and bottom.

Narrow gauge/mining/logging railroads had much steeper grades.

 

Matt

Another important factor in building a riser, you want to create
an 'easement' so that the rise is not so abrubt that the
front coupler of a loco diga into the ties, or that it's
wheels would lose contact with the rails at the top.

To create an easement, make sure the flex track joint is 2 or 3
inches back from the start of the rise...let the flex track find it's own
natural grade before supporting it. Do The inverse of that at the top.

Don

 

Matt

Another important factor in building a riser, you want to create
an 'easement' so that the rise is not so abrubt that the
front coupler of a loco diga into the ties, or that it's
wheels would lose contact with the rails at the top.

To create an easement, make sure the flex track joint is 2 or 3
inches back from the start of the rise...let the flex track find it's own
natural grade before supporting it. Do The inverse of that at the top.

Don

good tip, something I wouldn't have thought of. I don't know if I'll do what I have in the back of my mind. I didn't think that I would need so long a length to accomplish it.

On the Plywood Summit Line I have now, the rise from the base to the highest point is 11' long.

 

If your elevated track is going to go over a railroad track (as opposed to a road or a river), there is one other way to reduce the grade. Have the track that goes under the bridge go downhill, while the track going over the bridge goes uphill. This complicates your track laying somewhat, but you can greatly reduce your grade, while achieving the same clearance at the bridge -- depending, of course on your track plan.

 

One important factor to consider is this: if you have steep grades, your vertical curve into the grade will have to be that much longer at each end so that your powered wheels don't lose traction. That extra length means what lies between the two vertical curves must necessarily be that much steeper to reach the height you need to attain.

So, apart from the onus on locomotives to pull cars up steep inclines, and therefore severely limiting the length of train you can have if you can't double practically, you end up with grades that almost no railroad has. A 2.2% grade is quite severe for the prototype, and it generally is the practical limit for our toys. Yes, it's true: many layouts have to have grades considerably steeper to fit everything in, but you must compensate by using two engines, using traction tires, or cutting your trailing tonnage in half....sometimes all three if your grades exceed 4%.

 

I dunno, it's a toy and all of them are different. An 0-6-0 with no load can do 6%+ by itself and a two motor DD40 AX type can too, no problem. It's all about what you want to see and or IF you insist on "prototypical" then yea, 2-3% is a good "max" to choose. If you are not that concerned you can do what ever you can get away with. GO for it!

 

A locomotive getting itself up grades is earning no revenue for its owners. In fact, they're bleeding through the nose because they are paying the operators, and the machine consumes materials they must mine, purchase, grow, or steal. It also must be amortized, or paid monthly if leased, AND it must have repairs performed on it periodically. All of that costs money that a locomotive barely getting itself up a 6%+ slope isn't earning for them.

 

The chief problem at the top of a grade, as Don mentioned above, is that the "fixed" wheelbase determines what your locos will do. When the rearmost fixed wheel of the truck or driver arrangement is still on the slope, is the front one elevated enough to come fully off the rails (or the rearmost one, after the loco has crested). If it is, and your track is dead straight, your loco will likely drop back onto the rails without a problem. If there is any curve or wiggle in your track, one or more wheels may come back down outside the rails, causing a derailment.

Using a vertical easement makes this much less likely.

 

Some useful information,

"From: "Randy Hees" hees@astound.net
Subject: Maximum grade

The theoretical maximum grade for steel (or iron) wheels on steel rails is 25%. This assumes all wheels are powered, with clean dry rails. While a locomotive could climb this grade, it couldn't pull anything, so the limits on grade are economic rather than a physical.

Generally mainline railroads have avoided grades over 4%, and prefer grades of less than 2%. Some logging lines had grades in the 8% or greater range, but these were considered extreme.

The original line over Donner Pass had grades of 2.4%. The Harriman built second track reduced some of that (but not all) to below 2%.

When the 1905 Western Pacific was built, it had a condition in its charter than maximum grades could not exceed 1%.
—Randy Hees"

Note a 25% grade is 25' of rise in 100' of run and not a 25 degree angle. I just wanted this to be clear as I have noted some confusion in the past. With this you can see that a 100% grade is 100' of rise in 100' of run or a 45 degree angle from the horizontal, not straight up and down.

 

Very true, CT. I like to see my trains run as well, but never just as a locomotive struggling to get itself up my grades. Our hobby has room for all kinds of playing. I don't know anyone who just watches their locomotives attempt to get themselves up steep grades, though. Almost all of us like to trail a couple of cars at least, and that's why the steepest grades should be avoided. It's hard on the drives, hard on the pins connecting our steamers' rods and linkages (causing premature wear), and I can't imagine anyone not tiring of seeing a locomotive, and nothing else, in that never-ending and repeating cycle of the struggle on a grade that is prototypically unrealistic.

 

When I was young one of my favorite things was to run a Lionel 2026 engine and tender with just a caboose, a caboose hop, as it was called. The other thing was to see how many cars the 671 could pull up the grade. We would run it around the level loop to get it up to speed and then switch it onto the hill to see if it could make it up. With too many cars we had to back it back down the hill and try again. We never did get the other end of the hill connected back to the main line, so even if it did get up the hill we had to back it back down.

 

Somewhere around 25 years ago, maybe more, I built a 4X8 over-under layout, like
many new guys do. Big mistake. There is not enough room on a 4X8 to do a proper
grade. Back then I was using Tyco locomotives. They actually went up the grade fairly
well with a few cars. It was coming down that was the problem. Never had a derailment
up or down the grade. I had done a good job of laying the track. That layout could run
hours without a derail. Those Tycos turned into a roller coaster coming down grade.
Way to fast unless you almost shut the transformer down to nothing. It was very
unrealistic and I hated it. Fell out of love with that layout very fast. I still have it but it has become a storage table. I hated that layout. Planning a new layout around the walls
and would have plenty of run to do 2% grades. Right now I plan to not have any grades
on the new one. With the newer locos I don't think you would have the roller coaster
effect, but I am still going to avoid grades. I want to run longer trains and don't want to constantly be adjusting the throttle. Just my opinion, I hate grades, they look cool and
all, but can cause problems. Seems almost all new model railroaders want them. They
will learn.

 

The helper loco makes half the trips. He goes up the hill, then comes back down the same side. The primary loco goes up the hill, down the other side, then comes back with the empties, making a second trip over the hill (assuming he brings back empties). This could happen if the primary flow of goods were in one direction, if the destination city were at a significantly higher altitude so the reverse trip could be managed by a single loco, or I'm sure there are other scenarios. I would imagine there are situations where it makes more sense to send a single engine with more frequent smaller loads, and other situation where they would send dual locos in both directions. But every route would have its own unique 'best practice' for saving the railroad money.

Not that I know the history well enough to say any of these scenarios happened, but if someone figured out they could save a few dollars per trip by switching things up, they would have jumped on it.

 

The points about the fuel are a big issue - on some challenging climbs, a locomotive could often not even get to the top with any fuel left, and had to refuel half way up the grade. One climb like that was Raton Pass in southern Colorado.

My uncle "drove," as he always referred to it, locomotives for the Santa Fe Railroad. by the time I was born he had enough seniority that all he did was drive helper locos back and forth over Raton Pass between Trinidad, Co, and Raton, NM. (Operating helper locos was preferable and always taken by the most senior engineers because it meant you would be home most nights, not out of in California or Chicago with a long-distance train.). I made the trip with him twice when I was very young, once in the cab of a steamer, I think a 2900 class Northern, and later in the lead F3 of the Super Chief. The roughly 20 miles between the two stations involved about 28-26 miles of track and had an interim station about halfway up the Trinidad to peak side for refueling. It had been built around the time of WWI and was used all the time then. By the 1950s it was often not needed, but some of the old Mallets still used for their extreme pulling power, and not the most efficient locos ever made, needed to stop and refuel there, even then.

A heavy train pulled normally by, say, a big 2900 Northern, and assisted up to the top by two Mallets or similar, would often take half a day to make the trip of around 26 miles by track (about 20 miles between train station). The smoke from multiple engine working at full capacity was incredible - and probably not healthy, although my uncle living into his eighties and never had any lung-related problems.

Unusually for many RRs, on Raton pass the helper locos did not turn around at the top and head back, but continued downhill into Raton, where they were refueled again, and serviced if needed (often they did need it, it was only a few miles by all at max stress!), and when serviced and refueled, they helped trains coming the other direction, from Raton to Trinidad, climb over the pass.

 

As I indicated the real savings to the railroad was the time saved in getting the train over the hill, and on a busy railroad this was the most important reason for using helpers. The primary engine taking the train down the other side and returning with another train is irrelevant to the original question of getting the train up the hill. As Lee Willis said sometimes the helpers followed the train down the other side and helped a train coming the other way, It would all depend on the grade on the other side and the tonnage coming in that direction.

 

I'll bow out of this discussion with this comment: there is room in this vast hobby for all kinds of preferences. Those of us who have been around a while, a rather modest while only in my case, have come to accept that there are several avenues to disappointment that are almost universally experienced, with some variation. Derailments that defy discovery for their causes, grades and curves (often in combination, and almost always reported by newcomers trying out their ubiquitous 4X8 Plywood Pacifics), and engines that stutter and stall, or short out, for no apparent reason...these all quickly douse the flames of passion for the experience of running scale and toy trains. We who beg newbies not to try to cram steep grades into their limited spaces intend only good will.

Some people simply cannot be told; they have to learn for themselves.

 

wow, I really asked the wrong question I guess. Never thought it would turnout this way.

 

No, you asked a good question, it's just that some modelers are totally detached from reality.

 

I agree -- it was a very GOOD question, and I apologize for letting myself get drawn off in a completely useless direction. I should know better.

If the moderator wants to delete all the irrelevant comments, that's fine with me.