Ramblings from the Man Cave

Nice work Rich - the lever frames look good where they are!

 

Regs

 

Ian

So you've committed then? It had to happen sooner or later.

 

I've pondered the questions around interlocking several times for different layouts (most never built) and usually wind up back in the same place. Doing it electrically is simpler but doesn't achieve as much - the main problem being that it can't actually stop you pulling a lever... which mechanical locking will do. I've even built (with help) a mechanical locking tray for one layout.

 

Electrically you can, of course, refuse to clear the signals if the points are not normal or the relevant FPLs are not 'in'... but it's not quite the same.

 

Do you have room for a simple mechanical locking tray behind your frame? I'm guessing that it would not need to be too complicated and you seem to have some machine tools to ease the task... although changing the locking when your box is closing would likely complicate it a lot.

 

I did have an idea for using servos to physically obstruct the movement of levers (i.e. one servo to lock each lever). This might achieve the realism of mechanical locking with less of the metal bashing and would allow some of the more complex locking rules (e.g. closing), but it has not got beyond an idea and would be very dependent on the design of your frame.

 

Regards, Andy

I'm not particularly interested in duplicating the closing possibility of the real thing although it might be useful for lunch cover with unfamiliar operators.

 

I was wrong to think that writing a locking table would be reasonably straightforward. I am sure that many of my conundrums are due to the lack of signals and perhaps very little was actually locked in real life.

 

I keep returning to the idea of having the FPLs able to lock the switches when normal and the locks being required to release the signals with the signals then locking the levers that released them.

 

Leaving the electrical side of it alone such that the operator can ignore the signals is probably a sensible thing to do. This will allow the rewiring to be very very simple: just 5 micro switches will replace a good number of multiple pole double throw switches and much of the existing wiring can be joined up.

A wise chiuce Rich and good progress. Regarding the question of locking and the use of FPLs. Firstly on an exhibition layout you want to be careful that a minor problem will not stop all running as it can be embarassing. If you are using the solenoid type of point motor the FPL can operate a simple switch in the return for the point motor. With tortoise types I find that they need power on to keep the blades tight (no overcentre springs) so although cutting the power will stop them changing over it will also increase the risk of a wheel catching the blades. I have not tried servos so am unable to comment. If they do need power to hold their position then electrically locking via the FPLs requires more circuitry either a relay or some type of flip/flop driver. It is nearly thirty years since I played with those sort of things so I cannot suggest anything.

However bearing in mind your impending exhibition commitment, time is not on your side to go for a mechanical locking frame. Perhaps an electronic locking system which could be added later might be the option It could also be possible to make a removable PCB board which could be swapped for a simple one to remove the locking if needed rather in the manner of the blanking plug used on DCC socket.

Don

I was wrong to think that writing a locking table would be reasonably straightforward. I am sure that many of my conundrums are due to the lack of signals and perhaps very little was actually locked in real life.

Not sure, but I suspect that those signals that did exist would have been interlocked with the points and FPLs and also with each other. Other moves would be covered by hand signals. Hard to say how complex it would be without actually working it out on paper.

 

Given your time pressure, I think the idea of leaving provision for future interlocking (by whichever means you choose) is a good suggestion.

 

Regards, Andy

Should be simple enough to put a mechanical lock between the FPLs and their relevant levers. As they will be alongside each other, just put a bar across from the FPL. Then you have to reverse the FPL before reversing the point. 

 

GW practice is that FPL normally are out.

Nice one Rich - the fact that you hadn't fixed the levers previously was perhaps a sign that you weren't entirely convinced of the central location yourself...we just helped confirm that!

 

Looking forward to see progress

A wise choice Rich and good progress.

Don

Don, I don't intend to use point motors or servos. The movement will be driven by finger on lever through a mechanical linkage. I am using servo arms for cranks because I have a surplus supplied by my late father in law who was an aero modeller.

Nice one Rich - the fact that you hadn't fixed the levers previously was perhaps a sign that you weren't entirely convinced of the central location yourself...we just helped confirm that.

Pretty much.

Not sure, but I suspect that those signals that did exist would have been interlocked with the points and FPLs and also with each other. Other moves would be covered by hand signals. Hard to say how complex it would be without actually working it out on paper.

I've tried to do this a few times now and got myself in a muddle. I think I'm going lt go pretty basic and lock the switches normal with the relevant FPLs and the FPLs in each direction with the signal in that direction. There is one switch that will lock the FPL normal and release the doll, which will in turn lock the switch reverse. This is a compromise but seems sensible.

 

I'm thinking of building the locking tray in plastic.

I've tried to do this a few times now and got myself in a muddle. I think I'm going lt go pretty basic and lock the switches normal with the relevant FPLs and the FPLs in each direction with the signal in that direction. There is one switch that will lock the FPL normal and release the doll, which will in turn lock the switch reverse. This is a compromise but seems sensible.

 

I'm thinking of building the locking tray in plastic.

If you want to send your thoughts to me (when you're ready) then I'd be happy to look them over and help in any way that you need. It's a long while since I built mine but I still have the drawing stashed somewhere (and still have the frame attached to the layout too!). My tray is for a 20-odd lever frame and is milled from Tufnol. The moving parts are brass strip with steel pins for the bits that actually engage with each other.

 

Regards, Andy

If you want to send your thoughts to me

 

Could do. It sounds like your thoughts are similar to the ones I had.

 

It looks like Modratec have made interlocking frames with no levers for people. Not the cheapest option but it will save me time and headaches and I'm all for that! I've emailed so I'll wait and see what the answer is...