Modifying Lionel 151 semaphore for manual operation

I added a thermal shut off switch to my 151 semaphore in the event of an over heating situation occurring. The sensor will automatically turn off the semaphore at a certain coil temperature and turn on again after everything cools down. Seems to work well and can be purchased on Ebay for very little money. I just glued the sensor up against the copper colored coil base on the bottom of the semaphore. The sensors are available in different trigger temperature ranges of your choice. I chose one of about 120 degrees F. The sensor is very small and does not show from the outside of the signal once mounted.

Another approach could be to have a timer circuit to limit the length of time of the operation of the signal.

I have a NJ International Semaphore I got back in the 80s.  The original coil no longer worked.  I purchased a Tortoise Switch machine to mount under the benchwork.  I added a length of plastruct  L channel to the brass rod from the semaphore arm so it would extend below the plywood.  Drilled a small hole in the plastruct  L channel to fit the wire rod that comes out of the Tortoise Switch machine.  Took a couple of tries to get it right.  Wired the Tortoise Switch machine to an Atlas Twin.  I had to replace the Lamp on the semaphore also with a grain of wheat bulb.   So when I slide the switch up on the Atlas Twin the Tortoise Switch machine pushes the semaphore blade up.   When I slide the switch down on the Atlas Twin the Tortoise Switch machine pulls the semaphore blade down.  I do not have any block control to cut power to the center rail, but the Tortoise Switch machine has additional contacts that would allow you to kill track power when set to stop.  

You might be able to do the same with a 151 semaphore.  There is a bracket on the underside that holds the coil in place.  See if you can remove the coil to get to the "rack" that moves the semaphore blade.  There is a spring up at the top that holds the blade in place. 

My Semaphore, from the backside, Controls the Exit from my Yard Lead out onto the Mainline.

Steve

Here is a picture of the Tortoise Switch machine.  I made a wood bracket to mount it. Note the grey plastruct rod from the semaphore blade attached to the throw rod on the switch machine.

Steve

Here is a view of the 151 and its workings:

Steve24944 posted:

I have a NJ International Semaphore I got back in the 80s.  The original coil no longer worked.  I purchased a Tortoise Switch machine to mount under the benchwork.  I added a length of plastruct  L channel to the brass rod from the semaphore arm so it would extend below the plywood.  Drilled a small hole in the plastruct  L channel to fit the wire rod that comes out of the Tortoise Switch machine.  Took a couple of tries to get it right.  Wired the Tortoise Switch machine to an Atlas Twin.  I had to replace the Lamp on the semaphore also with a grain of wheat bulb.   So when I slide the switch up on the Atlas Twin the Tortoise Switch machine pushes the semaphore blade up.   When I slide the switch down on the Atlas Twin the Tortoise Switch machine pulls the semaphore blade down.  I do not have any block control to cut power to the center rail, but the Tortoise Switch machine has additional contacts that would allow you to kill track power when set to stop.  

You might be able to do the same with a 151 semaphore.  There is a bracket on the underside that holds the coil in place.  See if you can remove the coil to get to the "rack" that moves the semaphore blade.  There is a spring up at the top that holds the blade in place. 

 

My Semaphore, from the backside, Controls the Exit from my Yard Lead out onto the Mainline.

Steve

That sounds like a neat idea, but I wouldn't recommend trying to run track power through the contacts of a Tortoise. You could use it to drive a relay with higher rated contacts though.

I really like the idea of using a Tortoise to drive the arm of the 151. I've always felt the coil operation was a bit of a weakness in the design, as it is prone to overheating with prolonged activation. The Tortoise is designed to not "care" about activation time. It's always on, one direction or the other.

 I run the center terminal hot so I'm always lit up at my flag.

  Lamp to comm. via left terminal nut to outer rail/common. The coil terminal to iso-outer rail or pressure switch to comm... Your switch going to a common, etc; same thing.

The coil heat issue has a solution we have nearly all used in two activities.

One is activating a pinball flipper; the other is a whistle switch. Both use a high activation voltage and a lower voltage to simply hold a position.  This doesn't always eliminate an overheat issue, but greatly enhances needed off/cool time at least.

So, throw the Lionel Whistle and you see a high (5?) volt dc offset at halfway, then it drops to about 2-2.5vdc offset at full throw; the "holding voltage". You want to duplicate this action.

You could manage this a number of ways, the ideal switch/relay you'd want to be 3pos. norm off/temp on load #1 /on load#1+load#2.  I'm sure it is out there, finding them can be work

Leaf type Lionel buttons can easily be modified for doing this for temp action by restacking leaves and adding regulation/relays/etc.

Latching relays and such aren't cheap. Ebay modules? 

Simply test it for drop out voltage and remain barely above that to hold the flag down.  

A thermal polyfuse seems like a good idea too. The coil magnet wire dia. is needed to even begin to to guess well imo (dial caliper, micrometer, experienced guess).

Timed/Staged ebay modules might work well here for pull/hold AND for automation of the stations/blocks operation.

   I like my AF city station with timed stops.

Jackrabbit start-ups and e-unit cycleing are addressed by thermal in-rush limiter and a "keep alive" voltage to keep e-units from cycling , but not enough power to move a motor (post war/med-large modern).   (or simply lock out the e-unit).    In rush limiters start high, but lose restance fast. (a reverse of your old automotive ballast resistors for ingnition coils/starting).

It will wait and do a single timed stop, or do continuous stops. A modern module or relay manipulation of those two button circuits could add more interesting delays too.

I.e. you can manage this issue a number of ways too.

Thanks for all of the suggestions.  I like the idea of using the Tortoise switch machine.  I believe it's external contacts are only rated for 1A, so either using a higher-amp rated relay to cut track power or the DPDT switch should work.  One question:  if I use the Tortoise, will I need to remove the existing spring in the top of the semaphore tower?  If so, is that done easily?

Dale

Good question about the spring. I would think it could go. I don't think the arm is that heavy that the Tortoise couldn't handle it. The spring was really there to counteract the weight of the coil's plunger and pull it back up, and in many cases only did a fair job of that, not  quite getting it up to straight up.

I am not familiar with the guts of a 151 semaphore.  But, it looks to me leaving the spring in place would be fine as long as the Tortoise Switch machine has enough torque to compress the spring.      Looks to me you will have to take it apart by removing the coil at the base of the mast to get to the "Rack" that moves the semaphore blade.  You will need to extend the reach of the rack by adding an extension such as a brass rod.  You will need to be careful to leave the wire to the lamp intact.

Somebody else out there more familiar with the 151 want to jump in here and talk about how to take apart a 151.

Steve

Dale K posted:

... One question:  if I use the Tortoise, will I need to remove the existing spring in the top of the semaphore tower?  If so, is that done easily?

Dale

 

I can only answer about removing the spring. If you need to remove the spring, you have to pull off the silver cap at the top of the mast. Once the cap is removed, you will find the spring right at the top and then it is easily removed. A long time ago I had the MTH version of the 151 and I may have taken apart mosto of the signal, but the only thing I remember is that when I put it back together the signal did not work smoothly again, so be careful on taking things apart on this signal. I suspect that I might have gotten the mast misaligned when I put it back together again.

Why not save the motor retro fit for after the unit actually fails? 🙃

The idea isn't awful, but imo isn't worth trashing what may work fine as is 🤑 especially when the control can be used for either motor. (coil IS a motor too, linear )

Toggle the parking track and give the semiphore an isolated rail on the parking track with only enough acc.voltage to work, and match the semiphore bulb to that voltage.

The dual voltage is just a way to go even lower. DPDT works ok too (average 3pos vs "ideal" too for holding voltges ).

Burnt ones would be cheaper  

 And despite what was once noted; and very well might be true; I really also don't recall a bunch of these not working... I know mine has been left on a half hour-hour or more easy by toggle countless times; still kicking. I actually think maybe I fell asleep with it on a long time ago too...? 🤔 

I don't worry about it anyhow

 It and some town lights are on a 25w Marx tranformer phased to the other transformers and at about 4-8v I guess (?)... not quite half throttle; bright, and it snaps to attention.

Either way, imo, "you've got this". I'm going for popcorn and waiting for the video