Block instrument.

[TimeTraveller]

Hello all.

 

I'm not sure whether you can help me. I'm hoping you can. 

I have an old block instrument which I'm trying to wire up.

I will attach some photographs to show you what I'm up against.

It a GWR Spagnoletti Up line, Down line block instrument.

I have tested both coils and they both function correctly in both directions. 

What I would like to do and cannot work out is how to wire up one of the dials so it functions when I press either the white or red tapper.

I know it can be done as I've done it on all my other block instruments. I just cannot work out what wire goes where on this instrument.

A wiring diagram would be very handy but I cannot find much out about these specific instruments.

 

Any advice and help you can give would be greatly appreciated.

 

Many thanks.

 

[iands]

You could try contacting the Signalling Record Society (SRS), I'm sure someone there could advise. 

[APOLLO]

Google images, some wiring  diagrams shown.

 

https://www.google.co.uk/search?q=GWR+Spagnoletti+Up+line,+Down+line+block+instrument+wiring+diagram&tbm=isch&source=univ&fir=L7lcDTde0qiXQM%2CkqxWfsYT-wT4xM%2C_%3B2pQkeT2f0UgTOM%2CvdJKM0EUMEuHvM%2C_%3BJDoNJk0D4dOEzM%2Cou-3T7mnxU9oSM%2C_%3BW5BFiZiWxUZCyM%2C0d6gGA00p4jaeM%2C_%3BcMRgyBrzDKAHXM%2CbydUpmGWZ_Q84M%2C_%3BpUhD4pk_vWzD-M%2CHCtq6pAtLfzKEM%2C_%3BNYRHbnhhNwk8gM%2CyBOW_sz4hTYWIM%2C_%3BFJbSi5YM9LGloM%2Cu4El6y7nlcgkRM%2C_%3BbZ_5ccP_90qhWM%2C-dWblh3Xwjy8qM%2C_%3BwWtwp1z-OonWuM%2C7wEN7fcBcbFlXM%2C_&usg=AI4_-kSPZynGJFNEh3Q0vc8Diy61_I1vUQ&sa=X&ved=2ahUKEwiG8vj2ssL_AhUQhFwKHVP2CfcQjJkEegQIDRAC&biw=1536&bih=722&dpr=1.25

 

Also check out The Lymm Observatory site

 

http://www.lymmobservatory.net/railways/wiring_diagrams/wiring_diagrams.htm

 

Hope this helps

 

Brit15

 

[The Stationmaster]

Do you get any response at all from an indicator when a key is wired to it?   Don't forget they are keys - NOT tappers - on these instruments.

[Michael Hodgson]

I've wired a few block instruments but not one of these Spagnolettis - the only GWR instruments I've only wired were the 1947 pattern.

There are some conventions to the letters on all telegraph instrument though.

 

L is Line and E is Earth (return)

 

Z = Zinc (negative) and C (which I don't see in your photos) would be Carbon (Positive) of a Leclanche cell.  A block instrument normally has both sides of a centre-tapped supply (ie a +ve, 0 and -ve terminals) in order to apply the appropriate polarity to the line wire (via the indicator or the sending instrument, returning via the receiving indicators and Earth (or a return wire).  The polarity is usually chosen by a commutator, but in this case it is chosen by using the sliding wire to hold down one key or the other (or neither for Line Normal).

 

I'm told the GWR used opposite polarity to what the other companies used (just like their signals go down when everybody else's went up!)

You'd also need a bell circuit of course.

 

The chap at Lymm observatory has a good collection of instruments, but he's more interested in the North-West of England where he lives (Lymm is a village in Cheshire, I did my O-levels there).  His wiring diagrams are LMS and LNER standard 3-wire blocks, but the basic principle is the same, complications only come in when you add features like Home Normal Control etc.

 

 

[5BarVT]

8 hours ago, Michael Hodgson said:

I'm told the GWR used opposite polarity to what the other companies used (just like their signals go down when everybody else's went up!)

Certainly opposite to the SR.  Confused me when looking at the block switch at Exeter Central as it connected the block line to earth when switched out.  Eventually worked out that it was just a polarity change.

 

WR Standard block circuits show 12V to line (as that’s what the box battery would have been) through a 15 ohm resistor (in case the line goes short circuit).  +12V for Train on Line (red key depressed), -12V for Line Clear (white key depressed).  You shouldn’t need anything near 12V as the indicator is current driven and designed for miles of pole wire or cable in circuit.

 

I’m familiar with C Z L & E on a block bell meaning exactly what Michael said above.  Note that the top coil has L and E as it’s the non-pegging display- just shows what comes in on the line.

 

I suspect that Y and R are connected when the red key is pressed, and A and Z when white.  On a standard GWR block you can’t set LC and TOL together as it’s a single commutator, not sure if some of the extra connections on LC key are to prevent both being sent together.  Test out the keys to see which terminals are connected when.

 

If you could say where the wires disappearing though the backboard go to that might help.  Possibly a ‘bare end’ where they were cut off!

 

Paul.

 

 

[TimeTraveller]

10 hours ago, The Stationmaster said:

Do you get any response at all from an indicator when a key is wired to it?   Don't forget they are keys - NOT tappers - on these instruments.

The way I have currently wired it allows for the line clear key to function correctly. The train on line key does allow current to flow through it too.

[TimeTraveller]

46 minutes ago, 5BarVT said:

Certainly opposite to the SR.  Confused me when looking at the block switch at Exeter Central as it connected the block line to earth when switched out.  Eventually worked out that it was just a polarity change.

 

WR Standard block circuits show 12V to line (as that’s what the box battery would have been) through a 15 ohm resistor (in case the line goes short circuit).  +12V for Train on Line (red key depressed), -12V for Line Clear (white key depressed).  You shouldn’t need anything near 12V as the indicator is current driven and designed for miles of pole wire or cable in circuit.

 

I’m familiar with C Z L & E on a block bell meaning exactly what Michael said above.  Note that the top coil has L and E as it’s the non-pegging display- just shows what comes in on the line.

 

I suspect that Y and R are connected when the red key is pressed, and A and Z when white.  On a standard GWR block you can’t set LC and TOL together as it’s a single commutator, not sure if some of the extra connections on LC key are to prevent both being sent together.  Test out the keys to see which terminals are connected when.

 

If you could say where the wires disappearing though the backboard go to that might help.  Possibly a ‘bare end’ where they were cut off!

 

Paul.

 

 

Thankyou for your reply.

 

Just to add the wires going through the backboard I have simply put there so I could connect the coils up to a current while the front cover is on. They don't go anywhere.

 

Daniel.

[5BarVT]

1 hour ago, TimeTraveller said:

Thankyou for your reply.

 

Just to add the wires going through the backboard I have simply put there so I could connect the coils up to a current while the front cover is on. They don't go anywhere.

 

Daniel.

That’s exactly why the holes were there!

Going to try drawing in a text doc.  This is usually a bad move!!!

To make it work you will need two supplies connected together thus:-

 

+V —————— Y? ———

(-V)

 |——————— E ———

(+V)

-V ——————— Z ———

 

For the non-pegging dial wire an external switch to connect -V or +V to line

 

+V —\

              ———— ——L—[Indicator]—E—— (back to common power connection E)

-V —/

 

That should allow you to operate the top indicator from the switch, simulating the circuit from the box at the other end of the block section.

 

For the pegging indicator you’re trying to do something similar using the contacts operated by the keys but this needs an understanding of the internal wiring of the instrument.  For example, it looks like the LH E terminal is connected down to the keys, as are Z Y and R.  Where those wires go would help (if you can see).

 

Paul.