Hey all,
I am pondering using a speedometer to help me speed match my trains so I can MU them for big inclines… this includes diesels and steamies! Anyway, here are two viable options (besides using a ruler, stopwatch and ol’ arithmetic!) that I came up with… just wondering if any of you use these or have other options?
http://www.cp4e.com/trsped.htm
http://www.trainspeed.com/TrainSpeed1.htm
I look forward to all of your thoughts/input!
Brian
I use a Fleischmann Tachowagen, which appears functionally similar to the unit in first of your two links. It is also towed behind the locomotive, and gives readings in scale kph (as it is made in Germany).
From experience, I would always opt for something that you can tow, and not an item you place trackside - the latter means that you only get a read-out every time it passes by, whereas if the equipment is mobile, you get a constantly accurate readout to work with, in a far quicker time.
I use my tachowagen to successfully load the same 28-step speed curves into all my locomotives -one of the great things about DCC is that ALL of locomotives, of whatever make, can run in consist with any other, once their speeds are balanced in this way, via CV29 Bit4-1.
Brian M
I have one from “Model Railroad Technologies” that I got from Caboose Hobbies in Denver. $79.00. It can do HO or N scale. It has a “tunnel” that can be set anywhere over the track. As the train runs through it measures the speed. I love it. We had a lot of fun with it at our last open house. I set it over the track where the public could see and we played “guess the speed of the train”.
http://www.caboosehobbies.com/catalog/product_info.php?manufacturers_id=&products_id=45422
Brian,
Those speedometers seem like a lot of wasted effort if you are speed matching DCC locomotives. Usually just run them ‘uncoupled’ and see what happens. Here is my way of speed matching. I try to get most of my freight engines to run at a maximum speed of about 70 scale mph. Here goes:
CV02 - Vstart - Starting voltage(Set it to just start the engine as the throttle is notched up)
CV05 - Vmax - This one sets your maximum speed for the engine(throttle maxed out).
CV06 - Vmid - I set this one so that the engine runs about 30-35 scale mph.
If you have momentum or speed stabilization/BEMF turned on, you may need to adjust those CV’s as well. I have a ‘measured’ timing distance and adjust CV05 until the engine is running about 70 scale mph. Setting CV02 is just a matter of adjusting the value so that the engine stats moving as I advance the throttle.
I keep a log of all my settings using Decoder Pro. That way, if I pick up a new P2K GP9, I can use the prevoius settings for my other ones and start there. Once I have the engine ‘in the ball park’, I do the MU test with the engines uncoupled to see if they are matched. You can figure an HO scale 60 mph as about 12" per second.
Jim Bernier
Thanks for the input. I think the speedometers help match speeds better than any CV table alone, but perhaps this is just me and my relative newness to DCC (only 2 years of using it!)… Again, I appreciate all the input. I will have to try out Decoder Pro too… I don’t have a computer hooked up (yet) but it sounds fun!
Brian
A speedometer would only help you match the top speed basically. It wouldn’t do anything to adjust the characteristics of the engines - let’s say you have two engines that at full speed go 60 MPH. If it takes one 20 seconds to reach full speed, and the other 15 seconds, they’re not going to run together very well. You’ll still need to adjust the mid and start speeds (and momentum) CV’s to really get them running like one unit.
With all due respect to jrbernier and wjstix, using only two CVs (plus momentum in 3 & 4) to adjust the mid and start speeds is very “rough and ready”, and will not give you nearly as much running similarity as you would by inputting a whole 28-step custom speed-curve using CV29 Bit4-1 and then CVs 67 through to 94.
This allows you to give each speed step a specific speed, so that each locomotive you own (irrespective of manufacturer) will run at an identical speed at each speed step. This is why a wagon towed behind the locomotive IS so useful - you decide upon a specific set of speed levels you require for all your locomotives, and then adjust each loco to match each selected speed at each point in the 28-step curve, using the read-out from the towed wagon to adjust things accordingly. It’s best (obviously!) to do this on a loop where all the track is constantly visible, so that you can always see the read-out.
As an example, using this method, all of my locomotives will run at a scale 8mph at speed step 5, 12smph at step 7 etc. That is something you cannot achieve simply by using one start point, one mid point and one max point, especially with the different running characteristics of different manufacturer’s motors.
So the statement “a speedometer would only help you match the top speed basically” is incorrect. You will still have to adjust momentum individually too, with this method, but that is not too much of a problem, and takes only a couple of minutes to match them up, using a “master” locomotive.
This method obviously takes a wee bit longer than just using three CVs, but provides an almost perfect match. I reckon I can input a 28-step speed-curve into a locomotive in 20 minutes. My BLI and IM Cab-Forwards, Bachmann consolidations, Athearn Genesis and Proto F7s, Proto SD7s, SD9s, GP9s, FA/Bs, 2-8-8-2s and Trix mikados ALL run at identical speeds right through the 28
Brian;
Check out my link in my sig…On the bottom of the page, I have a great MPH calculator that works for all scales…
I personally use the very complicated and complex IGAI system which works very well for me. IGAI stands for “I GUESS AT IT”!..
Tracklayer
To quote Red Green, I use the most advanced and accurate tool I have: my eyes.
Kevin
Someone makes a GPS receiver designed to be strapped onto the arm a la a wristwatch. They only run a couple of thousand dollars apiece.
That’s too rich for my blood. Its been quite a few years ago but one of this hobby’s electronic whiz-kids designed a speed trap that used off-the-shelf ICs. Me? I will continue with a measured distance and the time proven “One-One-Thousand; Two-One-thousand; Three-One-Thousand; Four- . . . . . . . . . .”.
A 40 foot car passes a fixed spot in one second going 28 mph, a 50 foot car will pass a fixed spot in one second at 35 mph. Needs no batteries. Ken
I used to inspect equipment for the club, for locomotives I made a 10 foot mark and timed it for slow, mid, and high speeds. Then the operator had an engine card and could estimate the running speed based on throttle position.
I tried to make a speedometer car but the project waffed, never finished it. I decided doing a speedometer isnt really the big deal that it needs to be or could be, its a nifty oh thats cool, but I don’t thinkl for the model I will be trying to run at required “35mph” limits than to guessimate my speed. I think its an interesting idea if you have one to use to work the mind how fast your really going, but I will use my eye as my speed guess. I know when my train is slow, and fast…
I use 
Or I would, If I could find mine again…
25 bucks at walmart/target/hobbytown USA
Flashwave… how do you convert the readout to scale mph when you use that “gun”???
IronGoat
If your layout is equiped with block detection and you have JMRI, you can use the included Speedometer to give you scale MPH.
You can do it by timing the train as it goes around the layout. My last layout’s continous run loop turned out to be very close to one scale kilometer in length, so it was easy to work out speeds in KPH (If at train took 1 minute to go around the loop, it was going 60 KPH; two minutes = 30 KPH etc.) and then convert that to scale MPH’s.
BTW an easy way to measure your mainline is to make up a train of cars and juggle the cars of varying length around until you come up with a train that is say 3’ long. Then you can push the ‘train’ around the layout one trainlength at a time until you’ve gone all the way around the layout. Then multiply the number of trainlengths by 3’ or however long the train is. That way, you don’t have to try to use pi to calculate the curved tracks. Once you know how long the mainline is, it’s pretty easy to convert that to scale miles, and then to calculate how fast a train is going if it takes x amt of time to go around the layout once.
Of course, you can just mark of a shorter distance on the layout and do it that way, but the longer the ‘sample’ is you take, the more accurate the result will be.
Isn’t how each locomotive performs under load, and the size of that load, going to have a big impact?
I have been debating how I want to approach speed matching, and wondering how useful it would be outside of a MU of identical locmotives since once you put some cars behind the loco its speed is going vary from model to model, or so it would seem to me.
chris
Why the need for “gadgets”? I’m lucky, I guess, because I use mostly all 40 footers and all I have to do is count seconds for 2 cars to go past a tree, signal, building, or any other object. Real 60 mph = 88 ft/sec. HO is 1/87 scale and 40 foot cars are about 6" over the couplers, eh? So 2 cars = 1 foot and 1 second = 60 mph approximately, which my late '40’s/early '50’s freights would never do. But the rest is very simple math…2 sec= 30mph, 3 sec=20, 4 sec=15, 5 sec=12, 6 sec=10, 8sec=7 1/2, 10 sec=6, 12 sec=5. Enjoy! jc5729 John Colley, Port Townsend, WA
Good idea, John… I have all 40 footers also, so that’ll work just fine!!!
Thanks, Bob ( IronGoat )