Automatically changing the speed of a train

The easiest way to do that is install cruise control. MTH proto two and proto three already do this even in conventional mode.

 

 

 

There have been many changes in toy train control systems in the last 15 years. One of the latest is called cruise control, and there are trade names like Cruise Commander, Engineer on board, Odyssey, and the like.

 

The basic idea is that once you set the loco to a certain speed, it will maintain that speed up hill, down hill, around curves, on level track and so on.

 

To do this, there must be certain electronics in the locomotive. Some of these cruise control systems operate in conventional mode, where the voltage on the track sets the loco speed. MTH (a brand name) is the only manufacturer that does that as far as I know.

 

The other cruise control systems are all part of the various manufacturers command control systems.

 

In command control there is a receiver in the locomotive that controls the locomotive's functions in response to the operator's commands. The track voltage is set at maximum, or nearly maximum voltage and the loco only responds when it is addressed. With this system, you can operate multiple locos independently on the same track at different speeds and directions.

 

The system that Lionel invented is called TMCC, or Legacy, with Legacy being the newer but still compatible system. TMCC is available on many other manufacturer's locos as well as Lionel, and there are aftermarket installation kits.

 

MTH's system is called DCS.

 

The most popular system in terms of actual units installed is probably DCC, which is used in the smaller gauges, like HO and N.

 

There is a lot to learn about these systems, but this forum is a good place to do that.

 

Any command system requires that each locomotive have the command capability installed in it, upgrade kits are available for TMCC or DCS.

 

You can do it in conventional with some relays and diodes without cruise control.

 

Dale H

Dale, if I understand your suggestion, how do you deal with the same track section requiring different voltages depending on whether the train is ascending or descending?  That is, I'd think some kind of sensing components would be needed in addition to relays and diodes.

Even if you can do it with relays and diodes, it is sure easier and more consistent with cruise control!  Different consist lengths will change the dynamics of a fixed solution, where the cruise control just maintains the speed regardless of the load.

 

IMO, this is not a problem that lends itself to that kind of solution.

 

You can make a string of diodes or bridge rectifiers so that on the incline/decline you can tap more or less track voltage.  On the each end of the approach to the grade you can use an outside insulated rail section, each which will activate its respective relay. The relay on one end will latch electrically and the relay on the other end will unlatch it. This will determine train direction and whether track voltage is increased or decreased on the grade. You can also use a twin coiled latch relay instead. 

 

An example of the latch circuit to determine train direction is shown here,in this example it allows a crossing gate to work more prototypical. But the contacts could also be used to add or subtract voltage,for example +3 up hill and -3 down hill depending on whether or not the approach relay is latched or unlatched. Further relays could be used to eliminate roller jumping if it were a problem. If unidirectional relays are really not needed except to eliminate roller jumping as mentioned. 

 

http://www.jcstudiosinc.com/BiDirectionalCrossingGate

 

Dropping voltage with diodes is explained here

 

http://www.jcstudiosinc.com/Bl...=413&categoryId=

 

You can also put in a timing circuit in case the train stalls on the grade which will increase voltage..

 

You can also add a timing circuit to gradually accelerate the train up hill or down hill. This would work universally with all variations, but some trains may stop briefly.

 

Yes cruise is also nice,but most of my engines do not have it. Cheaper and easier to use a few relays and diodes than take apart all the engines and install cruise. I have over 100 locos.

 

Dale H

 

Would this be to sequence different relays with different voltages, or ?.  I've heard of, IIRC, 3 sections (relays) with different voltages to gradually slow an engine before a bridge-up. 

 

I suppose if you like to tinker with components you could use a triac and control the firing angle to change the voltage.  This could eliminate multiple high-current relays and should make it easier to smoothly ramp (rather than step) the voltage during changes as you'd get with relays and diodes.

 

 

A lot of ways to do it Stan

 

I just use relays and bridge rectifiers as a dropper. Individual relays, and their contacts can tap in different voltages in progression. This can be done with a repeat cycle timer and multi contact relays each relay powering the one ahead of it with sequential latching. The transition is not that noticeable because you are just jumping diodes in the string not disconnecting power briefly. Voltage stages can be as little as .6 volt increments. Acceleration rate is determined by the timer. I usually accelerate a train using 10, 4PDT relays in 10 steps. I also turn the bell on and off on start up.  Being a former pinball repair person I am comfortable with relay contacts and I have hundreds of relays in my parts bin..

 

Certainly solid state components can do the job also. Using a Triac you would need a circuit to stage output voltage gradually and protect it from short circuits I think..   I think some HO power packs used to have transistorized throttles for DC and had some sort of acceleration feature.

 

Dale H

 

 

No offense Dale, but this kinda' reminds me of the old saying.

 

If you're a hammer, every problem looks like a nail.

 

Most folks will not be inclined to connect half a dozen relays and diodes for a job like this!  I have no doubt you can make it work, having done this for yourself for a long time. I think you may be understating the complexity of getting it to work for varying environments, but I suppose that's another topic.

 

FWIW, I also fixed pinball machines when I was younger, and I even still have a few in the basement.  I'm quite familiar with relay logic as in 1960 I built a blackjack player out of old pinball and bowling machine parts, that project won the state science fair in my senior year of HS.

 

 

Has anyone retrofitted an engine that they currently own with cruise control?  is it simple to do?  if so what system did you use?  I have the polar express that I want to have cruise control and know nothing about how to install it.  so I will need something that is simple to install and easy to use. 

If you have one locomotive so far, I'd suggest you go the cruise control route.  Dale makes a valid point in that if you had 50 of them, I'd probably recommend considering his method.

 

I have put cruise control and sounds in many locomotives, both using the TMCC stuff from ERR and old Lionel TMCC packages, and using the PS/2 upgrade kits from MTH.

 

As for "simple to install", that's really dependent on your individual skills.  While I view most of this stuff as "simple to install", many would find it pretty close to impossible, it really does depend on your skill set.  Lots of folks in the forum here have installed this stuff, and many others have passed on the option and had someone else install it for them.  I'd guesstimate the costs for the parts to be in the $150-200 range, depending on the exact package you select.

 

I'm assuming you have the conventional control Lionel Polar Express set?

 

Another option would be to replace the single locomotive with one that already has cruise capability.

If you just have 1 engine,I would retrofit it with something. ERR used to make "cruise commander". Not sure how well it works in conventional. I asked over there once and they said it really was intended for command use but it should work in conventional.  You could convert it to MTH PS2 this would run over $200 to have it installed, I do not think your engine costs that much or if it is worth it to you.

 

To use 2 relays and some diodes,you would have to be able to make an outside and center insulated rail section on your existing track system. You would need 2 relays,maybe 6 bridge rectifiers,costing maybe $50. You would also need a transformer tap to power the relay coils. This all can be hidden under the layout,assuming it is not a carpet layout. I do not have any experience with fast track so I can not comment on the ease of doing this. Perhaps someone reading has installed cruise commander or used fast track. 

 

With either approach, it is important the the loco itself can take the grade without slippage or overheating the motor.

 

Here is a link to the ERR page and their products

 

http://www.electricrr.com

 

 

 

Dale H

Hi RoyBoy. I think that some of or maybe all the Lionel Odyssey engines also have Cruise control in conventional mode. Did you mean to say that only MTH has conventional only locos with cruise? With only one engine, I think the question would be, what's more important? Staying conventional with grades. Cruise control with grades. I believe some of my older PW engines coast pretty freely and the downhill grade with a voltage drop might not slow them all that reliably. It depends a lot on the momentum and how big of a consist behind it.

MTH engines with PS2 have cruise control,part of the PS2 system. They work very well both in command and conventional. Lionel Odyssey does also. Some early units are a bit quirky. 

 

Fred,

 

For free wheeling PW engines down a grade I have actually pulsed them down a hill,1 second on a higher voltage say 10 volts and 5 seconds on a lower voltage say 6 volts until it clears the grade. This eliminates stalling possibilities. If the center rail is insulated this could be done with 1 relay and a timer module. If only 1 train runs on a loop there is no need to insulated the center rail if 2 relays are used.  You could then use an insulated outside rail section on the approach and on the exit to work 2 relays. Since this is a latch-unlatch circuit these sections need only be 1 track section long. For bidirectional operation 4 relays I think for direction logic. I would have to draw it out but it could be done I think. There is more than one way to do it depending on requirements.

 

Dale H

 

 

Hi Dale, I really enjoy reading your posts. I am in the process of adding diodes to my conventional to smooth out the starts. Otherwise by PW switchers wreak havoc in my small classification yard. Also started playing with some relays for signal control. I think you method would work great but may be a bit advanced for a beginner. I would recommend making the simple voltage reduction first and suggest he practice running trains conventionally with the throttle. Or buy a cruise controlled engine.

Some of the newer Lionel engines say that cruise control can be achieved in conventional and give instructions for doing so. I have not tested this, nor has anyone I know tested this.

I wonder if the OP could look in the manual that came with his engine to see if it is capable of cruise control in conventional mode.

Hi Fred

 

He asked for automatic control. A few relays and some diodes is less advanced than cruise control,which involves solid state electronics,a tach strip or sophisticated measurement of backwards EMF. 

 

Actually if you sit down and draw a relay circuit,then trace it with all possibilities,then wire it up it should work.

 

Relays are just automated switches. If you have simple tasks you can use multi contact ones for simple logic. For complex logic you can use chips with and/or gates,etc and 5 volt power supplies instead of contacts. It is still a binary system,just like relays.  In many applications in the end you will still need a relay to switch or reduce power unless you use a Triac or transistor.  

 

The problem at hand here is pretty simple. I admit cruise is a better solution but I do not know of a aftermarket cruise add on that works in conventional. 

 

Dale H

 

 

And now for something completely different...

 

How about putting 2 mercury switches in the loco to connect/disconnect diode strings when on an incline?

 

Just thinking outside the box

 

Enjoying the discussion!

 

Ed

 

Hi RoyBoy, I believe that If it is not a command engine, it will not have cruise in conventional. My mogul has cruise in conventional, it just does not send all the voltage to the engine. Saves some for inclines and brakes on downhill. It takes a few feet of flat to figure out your speed and it responds a little slower than regular conventional. I also recall that only K-line had an unusual cruise in conventional setup. Very little documentation to my knowledge. Fred

The MTH PS/2 upgrade offers cruise control in conventional or command operation.  I tried the ERR Cruise Commander just now in conventional, and if it offers cruise in conventional, it doesn't work all that well.  I believe that Legacy locomotives also offer cruise control in conventional mode, however I did not test that operation.

 

I do believe that the MTH LocoSound conventional engines also offer cruise control in conventional operation, as they are strictly a conventional locomotive.

 

Hi Dale, I realize he is asking for an automated setup for a two layer reversing loop using what I think is a conventional RTR Polar Express Starter set. He also asked for the simplest solution but does not want to buy a loco with command and cruise. He also is interested in trying to upgrade his Polar Express to cruise control. I would love to see your schematic. Please post it and then our beginner can decide if it fits into his idea of simple. Please do not misinterpret because I learn so much reading your stuff and you have taught me and others a tremendous amount, but even with an engineering background I find it challenging. In my area of expertise I need to keep reminding myself that what appears simple to me is sometimes mind boggling to others.

Previous posters have mentioned a conventional locomotive, not to sound dumb, but what is that?  like I said I am new to all this.  also I am a little confused because I am not sure if the cruise control is what I want or if I want to do what Dale H suggested.  I have a simple layout and am only running one train.  so far I do not have any accessories on this layout.

Ed

 

I thought about using such a circuit in an automobile. An economy mode for air conditioning. A mercury switch could turn on the air conditioning only when a car rolls downhill.

 

In a train engine it could work if you could get a SPDT mercury switch and some diodes mounted in the engine if space allowed. When I started in instrumentation in power houses, Bailey instruments were all pneumatic and filled with mercury.  Later they were replaced by electronic 5 to 15 ma devices. I can tell you the air operated ones were just as accurate and more reliable. I think the EPA has all but banned use of mercury except for companies who contribute to political parties and market compact florescent bulbs. Tough to buy mercury switches now maybe. This mercury will later leach out of land fills and wind up in the water supply. I also used to service instruments in water treatment plants which removed heavy metals from water,an expensive process.  

 

Dale H

Hi Fred

 

I cant draw something specific right now. Here is a diagram of a latching circuit used in a different application linked before,a directional crossing gate (click to enlarge)

 

Forget the center relay it is not used. Look at relay A and relay B, just the coil circuits. These are the red and green wires and the 2 yellow wires from outside insulated Rails A and B. These DC coils are powered by a separate transformer which goes to a bridge rectifier. The minus of the bridge shares a common with the track transformer (green wire).

 

A train traveling clockwise has to roll over insulated rail A.

When it does the train wheels complete the circuit and energize relay coil A.

 

 Relay coil A latches through its common to NO contact set also in series with the contact set of relay B common and NC.This relay will stay energized even when the train leaves and advances to the center area where the gate is drawn..

 

When the train rolls over relay B,relay A coil is de-energized.

 

A train traveling counter clockwise will roll over B and relay A will be de-energized when the train approaches the crossing.

 

So depending on train direction,relay A coil will be on (latched electrically) or off when the train is over the crossing gate section.

 

Now relay A has a second set of contacts. In the above case it switches insulated sections on the crossing gate. Forget that and pretend the contact set is not connected to anything. We now have a common,NC and NO open for switching something,anything we want.  Pretend the crossing gate section is the up and down grade. We insulate the center rail of the grade section with plastic pins.

 

Now we wire up 5 bridge rectifiers 25 amp as shown in right of diagram here used for dropping voltage. "A" terminal of the track transformer goes to the start of the voltage dropper. This will give us about a 6 volt spread.

 

 

 

The -3 volt tap goes to the track center rail in the  loop.

 

The center insulated rail on the grade goes to the common relay contact.

 

The - 6 volt tap goes to the NO contact.

 

The 0 volt tap goes to the NC contact. 

 

When the train is on the rest of the loop it will always run with - 3 volts

 

A clockwise train will latch relay A before it approaches the grade,it will have -6 volts going down hill on the section.

 

A counter clockwise train will unlatch relay A,if it is latched. Going up hill it will have 0 volt drop or all of the transformer power.

 

Only problem left is the caboose with 2 rollers bridging power. 2 diodes or a polyfuse installed in it will take care of that. This could also be addressed with additional relays but I want to keep it simple.

 

The distance between A and B insulated rails is longer than the train run.

 

Relays should have 10 amp or more contacts.

 

Materials needed 5 or 6 bridge rectifiers depending on voltage drop desired. A SPDT relay. A DPDT relay. A small bridge for DC relay power but AC relays could be used also.

 

This system does not have memory so train should be parked off grade on shutdown.  A twin coiled latch relay could be used also if memory is important.

 

Hope this makes sense.

 

Dale H

 

 

 

http://www.frys.com/product/1908343?source=googleps&gclid=CJTqmfjt7LgCFe9aMgodbyoA_A

 

http://www.parts-express.com/pe/showdetl.cfm?partnumber=060-852&utm_source=google&utm_medium=cpc&utm_campaign=pla

 

http://compare.ebay.com/like/110782756227?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar

 

Jerry

A surprise,but for up and down you would need a SPDT,something with 3 leads and maybe 6 amps capacity unless you add a relay. On second thought I think you could use 2 mercury switches. Food for thought,thanks for the link. .

Mercury switches may not be sensitive enough to differentiate between level and realistic grades. For example the switch in the first link specifies a 12 degree tilt angle.  This corresponds to a track grade of over 20%!

Maybe there's an official definition somewhere but I think of a Conventional engine as one controlled by the voltage on the track...moving the transformer handle to adjust speed -  increase voltage to go faster, decrease voltage to go slower, interrupt the voltage to reverse direction, add some DC to the AC voltage to trigger the whistle or bell (if engine is so equipped).  "Conventional" operation is contrasted with "Command" operation where the track voltage is fixed and control is via a separate signal.

 

For simplicity I vote for cruise control. Converting you loco is fine but when you buy a new loco I think it is cheaper to buy the loco with cruise than to buy one and have cruise added.  

   Block control and other methods work  but for simplicity cruise is the way to go.

  All IMO; Don

Just mount the switch tilted a bit to get the desired angle But it would be touchy as grades are usually 5% or less on a layout.  Interesting concept using these switches..  Another problem is that the engine could be level but the cars could be on a grade. In contrast the outside insulated rail activates the relay if any car is on it.

 

The 2 relays I described using an outside insulated rail establish direction using 1 or zero logic. A third outside rail on the grade could establish position when the train is on the grade,also 1 or zero logic. The other relay contacts determine track voltage by switching power through a voltage dropper.

 

However if we were using a programmable logic controller and running a command system,we could feed this information into that and send commands if we knew the code. The weakness of current command systems is that they lack information on the position of the trains on the track. This could be done with relays or even a resistor circuit giving a 5 to 15 ma signal.

 

Dale H

 

 

The boys at Lionel are looking to change that soon with the new Legacy product announcements.

 

I am kind of at a crossroads here with our discussion, not sure if thats the right term, I have the Polar Express R.R. set.  I've had it for a couple years.  I had bought for it over the years the Additional cars, abbandoned toy car, hot chocolate car, diner car, and baggage car.  i found out in the beginning that this train would slow down to a creep after running for about 10 minutes pulling all these cars.  i googled and found out that the first generation locomotive was not powerful enough to pull all these cars so to remedy this i found out that i had to turn off the smoke feature on the loco and only pull 3 cars, im not too happy about that since i like the look of all the cars attached plus the $$ spent is lost on the additional cars.  so my thinking was to buy a newer generation berkshire locomotive that is more powerful that matches the one that came with the set.  If i go that route and buy a new locomotive do they make one that matches what came in the P.E. set as far as looks that has cruise control?  I would like to have my train look like the one in the movies or if it doesn't do I get one that does not have C.C. and do what Dale H. has suggested with diodes, switches etc.  I am not an electrician or an engineer so doing what Dale has suggested, which is greatly apprecitated, is a HUGE undertaking on my part because it is all new to me and I have no clue as to where to begin with that or even a firm understanding of it. Not sure if I were to buy a retro kit, which I seem to not be able to find or know what exactly i am looking for in one, plus the price of a new loco if it would be feesable to me.  Am i being too picky??

Fastrack track has bus bars on each piece to connect the outside tracks.  You can take them off and isolate the tracks, it's not that difficult.

 

Dale. So would this work for my lack of power or diminishing power when I try to pull more than 3 cars and have the smoke feature on? Also with what your proposing will this gel with controlling the speed of my loco when it's accending and descending?

I have the transformer that came with the set. I think it's CW-80 Transformer

All I can tell you is that automatically when the train climbs the grade it will have the throttle voltage,whatever it is set at. When the train is on the layout it will have 3 volts less than the throttle. When it goes down hill on the grade it will have 6 volts less than the throttle. These values are adjustable to meet needs. 

 

I can not comment on the engines ability to pull cars at a given voltage. Sounds like the Lionel loco is not good quality or there is some other problem. Most any Railking or Williams steamer or even a PW Lionel 2055 will pull 6 cars up a slight grade so i am not sure what is going on here.  Seems like this is an issue with the loco and not voltage input. Perhaps someone who has that engine will comment on performance.

 

I am not sure also of the tap configuration on the CW I never had one. Maybe someone can provide a link. I need to know the voltage of the accessory tap and which terminal on it is the common with it. I think this is backwards for PW type Lionel locos. On a PWZW the common is "U" for example. The CW should have enough power to run the train if you do not have a whole bunch of accessories hooked to it. The 3 relays will only draw 2 watts of power or less. I also assume you have adequate wiring and feeders. How big is the loop and how are you wiring the loop.? Your lack of pulling power could be due to voltage drop,dirty track joint etc. 

 

Just to add after reading your post again. Putting the smoke unit on should not slow the engine,unless there is some design defect or it causes a voltage drop to the track which is not wired adequately. If this happens and it is not a wiring problem, I would get on Lionel's case about it.  90 watts should be adequate run a 1 engine can motor train and a smoke unit and even a few lighted cars.

 

Dale H