We’ve noted that a number of our club members operate steam loco’s at unprototypical speeds due to lack of familiarity with the real thing(s) e.g. switchers going 60 smph.
A rule of thumb used to be that the maximum speed in miles per hour number was equal to the driver diameter in inches number i.e. a loco with 56 inch diameter drivers would have a max speed of 56 mph. That’s not to say that operating at such speeds would be efficient in terms of power output, fuel consumption or wear and tear on the loco, the track or the crew. It was usually none of these until modern steam with dynamic balancing, optimized boiler/fire/steam designs, roller bearings etc came along.
The following are suggested max speeds for steam locos currently being run at the club:
Those top speeds are probably pretty accurate. However, in practice, I don’t know with some of them how often they would approach that speed. The passenger engines could go that fast or faster, however engines with two-wheel pilots were usually freight engines, and would rarely go at passenger train speeds.
Today we’re used to seeing long freights with three huge diesels going 50-60-70 MPH down the mainline, in the heyday of steam long “drag” freights going 15-20 MPH would be more usual. A USRA 2-6-6-2 would be restricted to under 20 MPH because it’s small drivers caused counterbalance problems. Any speed above 20 MPH would start to damage the track with the pounding of the siderods and the weight of the engine.
2-10-0 Russians and 2-8-0 Decapods were generally used on wayfreights, often on lightly constructed branchlines where 20-30 MPH would be more common. Similarly an 0-8-0 with 51" drivers could maybe go 50 MPH, but in practice it would rarely get over 10-15 MPH in service. The DMIR used 2-10-2’s on ore trains where 30-35 MPH was the max, I don’t know how often 2-10-2’s would go much faster than that. If you had an express freight that needed to go 40-50-60 MPH you would get a 4-8-2 or 4-8-4 to pull it.
Keep in mind too that our model curves are much sharper than the prototype - a 33" radius curve in HO would work out to be about the tightest mainline curve a prototype railroad would have, and trains would be limited in speed going thru those curves at 20 MPH or less. So even though our model trains can take those curves at high speed, it might look better to slow em down a bit. [swg]
Train speed was(is) often determined more by track condition than by the engines on it. Our standard answer at Golden Spike on the speed of 1869 transcontinental trains is 25 - 35 mph. The engines could go faster but the track condition would not allow it.
dd
PS - we operate at about 10 to 15 mph max due to the short length of track now at Promotory.
There used to be a rule of thumb that a loco’s maximum speed should be the same as its driver diameter in inches. For more modern locos, that was adjusted upward to 1.1 times driver diameter.
On the N&W (which always did things their own way):
Class Y could approach, but seldom reach, 50mph. Usually operated at 25-35.
Class A would sometimes exceed 70mph (in passenger service) but usually operated in the 45-60mph range. Speed dropping below 30 on a grade called for a Y-class helper.
Class J (with 70 inch drivers) routinely reached 90mph, was once pushed to 114mph, theoretically could have maxed out at 140mph before dynamic augment became excessive.
As for the general rule - low-drivered locos seldom achieved their driver diameter in anything but runaway situations, while locos with 68 inch or greater diameters could usually exceed it and locos with 75-80 inch diameters were designed to exceed it (but might not, due to track conditions.)
OTOH, in Japan, passenger locos were restricted to 90KPH and freight locos were held to 70KPH, both well below their “rule of thumb” limit of 1MPH per inch of driver diameter. I have no problem with the low speeds, but some of my visitors (mundanes all) do.
Jus’ gotta jump in here and ask Where is the name MONASHEE coming from referring to a 2-6-6-2 saw this once before in a post. As i recall in every book or listing i’ve ever seen its always been referr to simply as a Mallet…
In 1930 the Grizzly Northern acquired two 2-6-6-2 USRA Mallets (generic name for compound articulateds of various wheel configurations) and after polling its employees, decided on the name “Monashee” for the class, after the Monashee mountain range through which the railway runs. [:)]
Real loco speed out on the full sized track is strictly controlled not by wheel size but by the ability to stop not to go fast.
The reason they put Engineers up front is simple aversion therapy. If the loco/train hits something they are going to be in the wreck.
Model train controllers that can’t practice low speeds/don’t want to/ae bored by it have “slotcaritus”. Sadly this is incurable in some people. It appears to not be fatal to sufferers but it can be fatal to friendships or club membership.
Personally I love to see just how slowly I can get any combination of loco/locos and car/cars rolling without (quite) stalling. This is far more absorbing. I’ve even been known to completely not hear the offer of a beer while creeping 3 ATSF GP35s and about 30 covered hoppers over a grade crossing so slowly theta I would guess the little people waiting looked for another route.
I’m the same way, especially with ore trains, just like seeing a Mallet or a couple of diesels rolling along at very slow speed. 12-15 scale MPH is about the norm, I’ve occasionally gotten them slower. My fastest passenger trains only run at 30-35 MPH.
I suspect it is a personality issue (or disorder??), some people just can’t go slow. (It especially bugs me to see somebody racing a switcher back and forth working a yard.) My sister, who isn’t very patient anyway, likes seeing the trains run but always complains that they’re going so slow. Of course, she lived many years in Duluth / Superior so having been stopped at a grade crossing for a 170 car taconite train maybe makes her empathize with the “little people” stuck at the grade crossing!! [:D]
Don’t think so. There are several factors regarding speed. The maximum speed of the engine itself has to do with how the engine is designed and balanced or how the engine overspeed is set. The speed of the train is set by the mechanical characterisics of the cars in the train. The speed of the track is set by its curvature, line and surface.
The only place stopping distance comes into play is the speed of a train downgrade or possibly the speed of the engine when traveling lite.
My rule of thumb - came from a 1966 article in Model Railroader - is to see how many 40ft car equivalents pass by a point in 5 seconds.
This is based on an HO scale mile being approximately 60ft (actual is 60.6 ft) and 40ft cars being 6 inches long. 1ft/sec = 2 cars/sec = 60 ft/min = 1 scale mile/minute = 60 scale mph.
As you count 5 seconds mentally, you count the number of 40ft cars passing the point you have picked out.
10 cars = 60 smph
9 cars = 54 smph
8 cars = 48 smph
7 cars = 42 smph
6 cars = 36 smph
5 cars = 30 smph
4 cars = 24 smph
3 cars = 18 smph
2 cars = 12 smph
1 car = 6 smph
So for a reasonable approximation of prototype yard switching speeds, it should take a 40ft car 5 seconds to pass any given point. A realistic 27 car steam drag freight up a grade (18mph) should take 45 seconds to pass a sign post or turnout stand near the summit. Do most of us operate that slow? Probably not. But it would make our layouts far more realistic.
The nice thing about this method is that it takes no equipment, just a little practice at estimating 5 seconds in your head.
Yes, Mark, I understand that quite well - when I wrote that I “travelled on” QJs I should have been more specific, and mentioned that on some trips I was firing them. As a result I got a very good idea of how well they steamed.
Actually, I was given a subscription to MR (1962) for my 8th birthday by my parents. They continued the subscription until I left home, and I continued it after that. So I was a youngster, but it wasn’t a back issue.
I had to give up most of my collection during the recent move to Colorado. I did keep my “precious few” - 4 boxes of model railroad books. Included in the precious few were most of the '60s issues - they had more valuable information (for my needs) than most later years.
Because my layout has lots of curves (minimum 30", with most larger) and lots of grades (up to 2.8%), and because I’m modelling a secondary line, I like to keep train speeds fairly realistic. With some heavy trains, I don’t have too much choice, as the curves and grades limit how much a loco can pull. I have posted speed limit signs around the layout, with the maximum allowable at 45 mph, although most areas are 35 mph or less.
I’m also going to install a couple of “speed traps”, where new operators can run a train a measured distance at a constant speed, then easily determine how fast the train was actually moving. I think that for many people, it’s very difficult to “guess-timate” the speed.
To make such a test area, I’ll mark off a distance of 5’ (actual) on any track, straight or curved. My plan is for a sign similar to my speed limit signs, but with a large “S” and the word “START” below, then a second sign 5’ later, with another “S” and the word “END”. These signs could be on their own posts, or attached to telegraph poles. I’ll post a table on the layout facia that gives speed values corresponding to the elapsed time for the train to move from “START” to “END”. For example, a time of 30 seconds to cover the 5’ equates to a speed of 10 mph, while a 9 second run will be at 35 mph. This is good only for HO scale. The idea for this comes from the September 2003 issue of RMC, which included a formula for calculating speed in any scale. The scale mph = .6818 x Scale Factor x Distance (in decimal feet) all divided by Time (in seconds). The scale factor is O - 48, S - 64, HO - 87.1, TT - 120, N - 160, Z - 220. (Distance i