I’m at the point of buying reverse loop circuitry, yet I’m not which one to buy. Tony’s? Digitrax? Any advice wanted. Since I am a solo operator most of the time, I probably won’t buy a PM-42. Therefore, I just need two single-devices. I’ve been buying from nscalesupply.com lately and couldn’t be happier, hence buying the digitrax from them, but I’ve heard a lot about the Tony’s being a good buy. Also, are there any limitations on loop length? (mine’s only about a foot long) Thanks
They all work. The real question is how often it will be exercised. I have one on a wye, that only gets tripped once when a train enters the wye. In that case I used the cheapest one I could - MRC. MRCs have a relay that physically moves each activation. It takes more time for them so the “short” is longer.
I have another situation in a loop-to-loop layout that the reverse gets tripped each time the train makes a circuit. It is in constant flux. I this case I chose a solid state reverser (I don’t remember if Digitrax or Tony’s). Solid state reversers are much quicker so the short is cleared faster. Plus there are no physical parts to wear out.
No, not any more than normal track wiring. Unless you are talking about being too short. If the “reversing” section cannot hold a whole train there is a chance that the locomotive could be going out of the section telling it to switch back while the caboose is still on the entry. This situation is more critical if all the rolling stock has metal wheels. So in that case yes. If the unit is being told to switch both ways simultaniously it could melt down.
I’m not quite sure what you mean Texas. Do you mean a TO? All I have is a short section of straight track which needs a reversing unit. So what you’re saying is that polarity of a reversing section is fixed until a loco runs into it, causing the reverser to switch polarities (if needed). Then the polarity switches back to its “fixed” position once the loco moves out of the section. Is this right? You’re saying that metal wheelsets of rolling stock affect the reverser too? I fail to see how these things work.
OK, I just read online about Tony’s PSrev. They recommend that if the reversing section is shorter than the train and the train has metal wheels, cut additional gaps in the rails just inside of the original gaps, about 1/2" away. what purpose does this serve?
The additional gaps recommended by Tony for use with the PSRev is to prevent metal wheelsets from causing the reverse module to short out if two sets of wheels should happen to be crossing both ends of the section at the same time. Tony’s PSRev is a circuit protector and reverse module combined, so a short caused by metal wheelsets crossing both ends of the reversing section at the same time could cause the PSRev to shut off the power. The staggered rail gaps prevent this from happening.
In addition to Tony’s having overload protection built in, the biggest difference between Tony’s PSRev and the MRC and Digitrax modules is that Tony’s is completely electronic and the others use mechanical relays, so the PSRev reacts much quicker than the relays. Normally, the speed of reversal should not be that critical at relatively slow speeds, but if you’re running something like an Amtrak Acela at full throttle through the reversing section the time delay for a mechanical relay to act could cause problems.
Yes, These work by sensing the short circuit caused when the train runs from one track onto the “reverser controlled” section. If it senses a short it flips the polarity of the electricity going to the “reverser controlled” section.
So you can see if there is a short on both ends, each telling it to flip the opposite way, there is a big potential for a melt down.
That depends on the specific reverser unit. If it automatically swithes back to its “fixed” position than it is a “non-latching” unit. If it stays in the position it switches to than it is a “latching” or “latched” unit. This does not change the issue of having an opposite short at each end of the reversing block.
Yes, anything that could jump the gap in the track between the two electrical blocks (auto-reverse and fixed) and cause a short-circuit will signal the auto-reverser unit to switch.
It prevents each wheel set from causing a short and trying to switch the unit. BUT there is still the issue of things like lighted caboose and passenger cars. The whole truck could still jump the rear gap. I always recommend people re-evalutate the track plan and try to find a longer (at least one train length section) that can be used as the auto-reversing section.
Lighted caboose and passenger cars are going to have no effect on the PSRev or any other reverse module because light bulbs are not polarized like an electric motor or decoder input. But if a passenger car should be the exact length of the reverse section and both trucks are shorting it at the same time, then you could have a problem.
I’d have to take exception to that statement. Lighted cars will cause the reverser to switch. This won’t affect the lighting in the car, but the reverser will go over because it’s sensing a short. All that’s needed is for the metal wheels to cross the insulated line. If the cars have “all wheel power” then the front and rear wheels are connected, so the reverser will sense a short even if the car is straddling the insulator.
You don’t even need lighted cars for this. If a metal wheel touches both sides of an insulated gap, then there will be a short if the polarity doesn’t match.
I’m using a couple of the Tony’s reversers, and they work great. The reversing is so fast that I don’t even notice it. The built-in circuit breaker lets me keep running the rest of the layout when I have a short on the reversing section, too.
My HO reverse section is a crossover from one side of a loop to the other. The reverse section itself is only about 4 feet long, and I occasionally run a train through it that hits both ends with metal wheels at the same time. Just bad luck, but I plan to re-wire this to add another foot or so to the reverse section. I think you’ll find that 1 foot, even in N, is too short.
Sorry, I don’t know where you got an idea like that, but polarization has nothing to do with it. It is simply related to the detection of short circuits and anything electrical that bridges the two sections of track can cause it.
The Bellingham Society of Model Engineers is a large HO DCC club which has used MRC reversers for about 6 years. We have not had any trouble with any of the six or eight that we have. They are a good value. We also use a couple of Tony’s products where we want to isolate a section of track and have circuit breaker protection with a reverser. We have had no problems with Tony’s products. None of our loops are of short distance. On our former layout, we had an MRC reverser on our turntable and it worked fine, but of course there were no engines crossing it at high speed.
I get it. So if I don’t have any rolling stock with both front and rear metal wheelsets electrically connected somehow, I should be alright with 1/2" to 3/4" “dead” gaps. The loco will obviously bridge the gap and as long as I don’t have another car or loco bridging the other end, it should work. I don’t plan on having any interior lighting or any reason to connect front and rear wheelsets. Eventually I will switch over to all metal wheels for signaling, but that still shouldn’t cause any problems. Thanks guys…this helps clear things up!
As any metal wheel on one side of the truck crosses the insulated gap that’s a short the reverser sees and swaps polarity. If that is happening at both ends of the reverse section you’ve got a problem.
Doesn’t matter if the trucks are connected or not it’s just an individual wheel thing.
Ken.
I have a Digitrax AR1 and have found it to work well. The AR1 has an adjustable trip setting which provides some added flexibilty.
I couldn’t set up my AR1 to work reliably, one loco would work but two would have a different setting then two with sound would be different again. I gave up on the AR1 biffed it and got a PSREV from Tony’s
Ken.