When I run a TMCC engine past a point in my layout where there is a nearby garbage truck with flashing led lights the train slows down and often will stop. It seems that the flashing LED's interfere with the signal from the Legacy base to the engine. Does this sound like a possible cause or should I look elsewhere?
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hard to imagine how that would be but try turning off the LEDs as a simple test.
If the power to the truck's lights shares the track common (outside rails), it can interfere with the TMCC signal. I've seen this with a variety of metal accessories such as signal towers where the typical electrical connections ground the metal tower to the track common.
How are the wires to the LED's routed? Do they parallel the track for any length?
Just turn them off and see if the issue disappears.
I turned off the power to the garbage truck. The TMCC engine still slows way down in this short segment of the track. So, that's not the cause. What other causes would interfere with the TMCC signal? If I increase the speed of the engine then the locomotive barely makes it through this short area of track and then it regains its speed. MTH engines run through this area without difficulty.
@triplex posted:I turned off the power to the garbage truck. The TMCC engine still slows way down in this short segment of the track. So, that's not the cause. What other causes would interfere with the TMCC signal? If I increase the speed of the engine then the locomotive barely makes it through this short area of track and then it regains its speed. MTH engines run through this area without difficulty.
Well, there is the clue.
If it was really losing TMCC signal it would stop dead- NOT slow down.
Sounds like you have a power problem with bad connections or track feeds in that area, combined with running either Lionel engines that do not have Odyssey or cruise, or are just more power hungry (draw more current- and are more sensitive to rack voltage drops) than your MTH engines.
Again, the loss of speed on TMCC Lionel based engines (especially ones without Odyssey- AKA Cruise- maybe even AC motors), more points to back or loose track pins and connections, and lack of a feeder in that section of track - causing a voltage drop that increases (even less voltage) in higher current draw situation.
MTH PS2, PS3, and Locosound engines all have cruise/speed control that is tachometer based. They can sometimes easily maintain a controlled speed even with lower track voltage- the electronics attempt to maintain speed. Also, in my experience, MTH engines draw less current and are much less sensitive to source voltage (assuming running under DCS control).
Also, if engines lose signal- they either keep doing what they were last doing, or stop. They do not slow down, and worse, do not speed back up- that's not how that works at all.
To Vernon's points, any recent wiring changes? Has this just started out of the blue? Is it possible to get a voltmeter reading during operation?
If I connect a jumper wire to the outside rail and connect it to the Legacy base would that improve the TMCC signal in that specific area? Can you connect more than one wire from the Legacy base to the track? The engine does come to a complete stop unless I give it a lot of voltage to get through this short segment (less than two feet) of track.
What's the item# of the Tmcc locomotive. I.E. 6-xxxxx
Signal issues typically cause tmcc /legacy locomotive to stop completely, not slow down.
This could be an engine without cruise control, which is pretty much standard across Mth engines, but not all tmcc engines have it
Does this engine have a pullmor motor?
@triplex posted:If I connect a jumper wire to the outside rail and connect it to the Legacy base would that improve the TMCC signal in that specific area? Can you connect more than one wire from the Legacy base to the track? The engine does come to a complete stop unless I give it a lot of voltage to get through this short segment (less than two feet) of track.
NO stop. I'm concerned we have some terminology problems in communicating.
#1 your symptom is NOT loss of TMCC signal. Trains do not slow down and then speed up as signal is lost and then regained. Instead, they keep going or in extreme cases stop dead. Yes, the train stopped, in your scenario, but it was NOT TMCC signal because when you had the train go faster, it slowed down then resumed normal speed.
#2 While you can connect more than one wire to the base, no that does not improve signal nor likely would it help in this scenario. Instead that is an entirely different topic about adding ground plane or earth grounded wires under or near the area where signal is lost. Again, no, what you described is not a fix in most cases.
#3 Throttle and Voltage are NOT the same thing in this context. Again, you are in command mode with what is supposed to be near constant source voltage on the track (roughly 18V AC). When you go faster, you are telling the onboard electronics to give more power to the motor- assuming the electronics are getting that 18V from the track.
In your scenario- you appear to have a section of track with either bad contacts to adjacent track sections or just a dirty section. Either way, the train is seeing lesser SOURCE Voltage from the track in that section due to resistance- likely at the track pins to rail connections or whatever track system you are using.
You need to fix your track power distribution- either add a bus or star feeder set of wires (both middle 3rd rail and outer rails) set of wires, and check track connections for being tight and clean good electrical connections on all 3 rails between each section of track- BEFORE and AFTER this problem section.
If I disconnect the Legacy base and run the engine conventionally it runs through this area of track normally. It does not slow down or stop. It only stops when the Legacy base is connected to the track. And, by the way, the base connection to the track is at a distant location.
Again, no, adding more base wire connection points is typically not a fix in this scenario. If you insist it is TMCC signal, then you need to add an earth grounded wire or plane (can be aluminum tape as an example) often wired to either true earth ground or the ouside ring connection of the TMCC base power jack (or pin 9 of the serial connector). Again, adding a ground plane increases the TMCC signal because it is the other half of the antenna.
When your engine comes to a complete stop. Is the headlight flickering or is it off ?
Vernon, he states MTH engines have no issues. Would running one at a slow speed and using the Check Voltage soft key give any indication of a bad section of track ? Or just using the Track Signal test to see if the signal goes south for a few feet.
I agree it sounds more like a track or locomotive connectivity/power issue than a TMCC signal issue. Check track for cleanliness and rust in this area, check locomotive wheels for crud. These are changes over time that could affect this specific loco on this specific section of track, which is likely your problem, not the TMCC signal.
@triplex posted:,by the way, the base connection to the track is at a distant location.
If you are saying your track and power distribution is correct, then the shear distance of where your TMCC base is connected to your track has no bearing on signal. Again, if your outside rails are all common, then this implies good electrical continuity, then distance and one single connection to the base is not the problem. TMCC doesn't need and doesn't improve because of bus or star base connection to multiple feed points on a layout.
Again, (Edit- provided it actually is TMCC signal) more likely fix is adding ground plane above, below, or adjacent to the problem area, using wire, mesh, foil, or other conductive material earth grounded (and not in any way electrically connected to the track). It is merely nearby.
@Dave_C posted:When your engine comes to a complete stop. Is the headlight flickering or is it off ?
Vernon, he states MTH engines have no issues. Would running one at a slow speed and using the Check Voltage soft key give any indication of a bad section of track ? Or just using the Track Signal test to see if the signal goes south for a few feet.
Valid questions/troubleshooting. Good ideas for sure.
Not clear from the preceding posts if this issue has been observed with more than one TMCC engine.
We would love to help you. Can you please post a video showing a few different locos navigating the "problem" section? And especially one of the loco that's having the problem. Make sure the video clearly shows its headlight as it navigates the section of track in question. If it's losing the signal, that should be apparent.
Vernon is correct. Signal issues do NOT cause engines to slow down. Let's clarify the problem with some specific information to better help you.
1. What is the make and model number of the problem engine.
2. What is the power source used to power the track. 180 brick, zw, zwl, cw80...
3. You stated that it runs ok in conventional mode. How are you running conventional? And are you increasing the power and decreasing power as the engine runs around?
4. What are you setting the voltage to when running command?
5. Is the track level in the problem section ?
6. Is the the track straight, curved? If curved, what radius?
7. Does the headlight blink when running command? Blinking headlight is a weak signal indicator.
There can be many factors which cause an engine to slow down. I think once we get some more specifics we can better guide you.
I run conventionally with MTH Z-4000 transformers. No MTH engines have any issue passing through this straight section of Gargraves track. Every Lionel engine either comes to a complete stop with the headlight flickering or slows down drastically so that I have to spin the big red knob on the Legacy Cab controller to get the engine through this section. As soon as it advances about one foot it runs normally. Sometimes, because this section of track is beneath a platform with buildings and lights I have to disconnect the Legacy base and run the Lionel engines conventionally. They run fine through this section of track like the MTH engines. The track is level and and the TMCC voltage is set at 18 volts.
This screams out TMCC signal issues, first step is to add an earth ground wire near that section of track. The most desirable location is above the track level.
Whenever I've suspected a signal problem I've held my hand a few inches above the loco as it passes through a problem area. This seems to improve the TMCC signal reception. If it works then you definitely have a weak signal in that area.
Also you could plug an extension cord with a ground conductor in it into a grounded receptacle and run it near the problem area. That will temporarily add a ground plane to the area so that if it works then you know you need to add a permanent ground plane.
Ken
I took Ken's advice and laid a three prong plug extension cord next to the problem section of track. I then plugged the extension cord into a wall receptacle and by golly it worked! My Legacy Berkshire ran through the area normally. Now, What is the easiest way to establish a ground plane in that area which is somewhat hard to access on my layout? By the way, thanks to all of your Forum members that have helped me solve this problem which has eluded me for years.
Milt
TCA 87-25879
Can I place the ground plane wire beneath the track rather than along side the track? The surface beneath the track is 1/2 inch plywood.
You mentioned an above platform with buildings that is over the troubled section. You could just place it on the underside of that. It would then be out of sight and not noticeable. It would accomplish the same thing as placing your hand over the Loco.
@triplex posted:Can I place the ground plane wire beneath the track rather than along side the track? The surface beneath the track is 1/2 inch plywood.
Don't put it under the track, you're defeating the purpose of the earth ground wire. Put it above the track.
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