Jump to content
 

Train spotting at Finsbury Square


31A
 Share

Recommended Posts

  • RMweb Premium
7 minutes ago, 31A said:

I've spent the last few weeks working out how to motorise the turntable.  To be honest, I was slightly underwhelmed by the new Peco turntable motor; as it's turned out not to have an indexing feature and relies on lining the rails up by eye, I thought it was quite a lot of money for what it was.  I'd used Meccano to drive a Peco turntable on a previous layout (albeit that also relied on lining up the rails by eye) and having a box full of it for about the last 50 years I thought I'd see what could be done with it.

 

One thing that has often struck me about model turntables is that the motion can be jerky in a way that isn't possible when 100 tons of loco is being turned.  Also if possible I wanted the table to stop automatically when in line with the rails feeing it.  I thought flywheels would be a way to eliminate jerky motion and indeed they were, but they imparted so much inertia that it was impossible to stop the table in line with the rails!  The real one at the NRM seems to have the same problem, when it is being demonstrated.  So I've come up with a mechanism that disengages the drive at the same time as the current is cut, and the lock drops in.  That way, the flywheels can carry on rotating until their energy is dissipated, whilst no longer turning the table.

 

Here are a few pictures of it.  The description may sound like an article from "Meccano Magazine", as I will try and use part descriptions from the catalogue, although "Microswitch" wasn't in the Meccano vocabulary, and "jam jar lid" didn't feature often either.

 

The first picture shows the "control" side.  The motor, which is from an old tape recorder, drives Shaft A.  The blue Pulley is one of the flywheels, and behind it is a 1/2" Pinion which engages with a 1 1/2" Gear Wheel on Shaft B, which also carries a Worm.  Shaft C is the "Control Rod", with the Control Lever on the end - on the layout this is much longer and comes out to the front of the baseboard.  Among other things, turning this operates the micro switch which energises the motor.   On the finished version, the turntable itself is attached to the top of Shaft D.  As can be seen, at the bottom of this shaft is a 3 1/2" Gear Wheel, with a jam jar lid attached to it.

 

The ends of the green girders at the top are attached to wooden blocks under the baseboard, either side of the Peco turntable well.

 

IMG_3091.jpg.bab359db31bcc1a6588d9fb4b88630cd.jpg

 

The next picture shows the "drive" side.  The motor drives by belt a 1" Pulley, which is behind the other flywheel.  Originally I used bigger pulleys as flywheels, but they caused a lot of vibration - they were probably no longer true!  In this picture you can see the "Follower" (E) and the Tension Spring (F) which causes the Control Rod to drop when the Follower reaches a notch in the side of the jam jar lid, which corresponds with the position of the rails on the baseboard.  When this picture was taken, I was just testing that the table could be made to stop accurately enough after turning 180 degrees; to do this there are two notches in the side of the jam jar lid, which obviously must be exactly opposite each other.  On the layout, the table will serve two roads, and there are now additional notches to cater for this.

 

IMG_3095.jpg.785fe0304dd4f38b280fc3e2420e1cb4.jpg

 

 

Next is a close up of the jam jar lid and Follower.  The Follower rises and falls in the slot made from a 3" Formed Slotted Strip - as supplied these are curved, but this one has been straightened and then bent though 90 degrees so that the slot is vertical.  This eliminates any side play in the follower, when it has dropped into the notch in the jam jar lid, and holds the table tightly in place.  The follower is carried in a 1 1/2" Double Angle Strip, which is attached to a 1 3/8" Bushed Wheel on the end of the Locking Rod.

 

IMG_3096.jpg.649fc33374fffb4195eca68017636cf8.jpg

 

The last picture shows how it works!  The Control Rod carries a Coupling (G) which holds a Threaded Pin, the other end of which engages in one hole of a Fork Piece on the Locking Rod.  Moving the Control Lever clockwise causes the Fork Piece to lift the Locking Rod.  This lifts the Follower (I) out of the notch in the jam jar lid and activates the microswitch which starts the motor.  Crucially, it also lifts the 1 1/2" Gear (H) as this is on a Rod with Keyway, meaning it can slide up and down whilst still turning the rod.  Lifting this gear engages it with the Worm on Shaft B and causes the Final Drive Shaft D to rotate.  Once the table has started rotating, the operator can let go of the Control Lever because the Follower runs on the rim of the jam jar lid, holding the Locking Rod up which keeps Gear H in mesh and the microswitch closed, until it reaches the next notch in the jar lid, when it drops, cutting the power, dropping Gear H out of mesh, and locking the table in place.

 

IMG_3097.jpg.0ba89ec56d26f05bf0a50999a592c48c.jpg

 

Quite a lot of experimentation was necessary to get this all to work, and several elements needed careful adjustment but it has now been installed and tested on the layout, and so far (touch wood) is working quite reliably.

 

For the moment it is temporarily fed directly from a 6v DC supply, but when I make the control panel for the Loco Yard I will pass the motor feed through the track section feed switch for the turntable rails so that a loco can't be driven whilst the turntable is rotating, and vice versa.  At the moment it only rotates anticlockwise but I will also incorporate centre off DPDT switch to reverse the polarity of the turntable feed so that it can rotate in either direction, with the centre being an "Emergency Stop" switch; something which is sadly lacking at the moment!

 

 

Well I'll be slapped in the mush with a wet parsnip! I can verify that the turntable works like a Victorian clock mechanism and does indeed move in a very prototypical way, 

with just the right amount of 'speed. In fact it is quite hypnotic and I would happily sit for many minutes just moving loco's on and off shed

 having turned them.

Truly remarkable drive system that I had not seen apart from the operating lever.

Heath Robinson.

  • Like 5
  • Thanks 1
  • Funny 1
Link to post
Share on other sites

  • RMweb Gold

Nice you gotta love a box full of Meccano. I too have a box full of the stuff. You can never have too much Meccano, it's very much like sausages in that respect.:jester:

regards Lez.

  • Like 3
  • Agree 1
  • Informative/Useful 1
Link to post
Share on other sites

  • RMweb Gold
On 24/10/2019 at 08:47, 31A said:

 

 the engine men's bothy is similar to the one at KX although smaller

Bothy? Excellent, but possibly not a familiar term to many Londoners! About 40 years ago I was SM at Dartford, and most Saturdays we had a meeting with the extremely militant Slade Green Guards' LDC. I had an excellent assistant, also called Ian, and he used the term bothy in the minutes on more than one occasion. He came from Kircaldy. 

  • Like 3
  • Informative/Useful 1
Link to post
Share on other sites

  • RMweb Gold

Whereas the ditty I was introduced to in Reading was ‘to the cabin you must go’.

The other Scottish word I like to try to introduce into documents is ‘outwith’ (particularly south of the border!).  First seen by me at North Queensferry on an official sign relating to Forth Bridge access.

Paul.

  • Like 4
  • Agree 1
  • Informative/Useful 1
Link to post
Share on other sites

  • RMweb Gold
16 minutes ago, 5BarVT said:

Whereas the ditty I was introduced to in Reading was ‘to the cabin you must go’.

The other Scottish word I like to try to introduce into documents is ‘outwith’ (particularly south of the border!).  First seen by me at North Queensferry on an official sign relating to Forth Bridge access.

Paul.

I am pure southerner - Surrey born and never lived north of the Thames - but regularly use 'outwith' because it is such a useful word! 

  • Like 3
  • Agree 2
Link to post
Share on other sites

  • RMweb Premium

I agree, I don't think it's a 'Southern English' word (I don't think I've heard it used in Yorkshire either, at least not on the railway), I just used it in quoting back the person above my post to avoid getting into discussion about it!!

 

  • Craftsmanship/clever 2
Link to post
Share on other sites

  • RMweb Premium
28 minutes ago, 5BarVT said:

Whereas the ditty I was introduced to in Reading was ‘to the cabin you must go’.

The other Scottish word I like to try to introduce into documents is ‘outwith’ (particularly south of the border!).  First seen by me at North Queensferry on an official sign relating to Forth Bridge access.

Paul.

 

At one time, the BR Travel Centre I worked in had to send some accounting documentation to a centralised accounts office in Glasgow and we were bemused when they sent  discrepancies back to us caused by an item being "accounted for outwith the correct Period"!

 

  • Like 2
  • Friendly/supportive 2
Link to post
Share on other sites

  • RMweb Premium
1 hour ago, 5BarVT said:

Whereas the ditty I was introduced to in Reading was ‘to the cabin you must go’.

The other Scottish word I like to try to introduce into documents is ‘outwith’ (particularly south of the border!).  First seen by me at North Queensferry on an official sign relating to Forth Bridge access.

Paul.

Forbye that, "forbye" is another useful word that I've never heard used outside Scotland or by Scots.

  • Like 1
  • Informative/Useful 3
Link to post
Share on other sites

  • RMweb Premium
1 hour ago, 31A said:

I agree, I don't think it's a 'Southern English' word (I don't think I've heard it used in Yorkshire either, at least not on the railway), I just used it in quoting back the person above my post to avoid getting into discussion about it!!

 

 

Yorkshire would most likely be hut with the 'h' optional.

  • Like 1
  • Agree 1
  • Informative/Useful 1
  • Funny 2
Link to post
Share on other sites

  • RMweb Premium

Thinking about these different names for bothies etc., when I was a Guard in Yorkshire I think train crew often just said they were going to "the room", i.e. short for "Mess Room" or maybe in earlier times "Guard's Room".

  • Like 1
  • Informative/Useful 2
Link to post
Share on other sites

  • RMweb Gold

Lobby was the normal term I was used to. Room perhaps implied a depot where a supervisor had an office, while the traincrew had their own designated space for PN etc.

 

Lobby was also used for non-traincrew accommodation, e.g. carriage cleaners, shunters etc. I think it was New Cross Gate upside where the cleaning ladies' lobby door bore dire warnings about uninvited guests and their immediate future. 

  • Like 2
  • Agree 1
  • Funny 3
Link to post
Share on other sites

  • RMweb Premium

Yes we had a lobby as well, but that tended to refer to where we signed on, received our machines from the clerk, and the notice cases etc. were located.  The "room" I'm thinking of was more the Train Crew Mess Room itself and might refer to a very big facility like in Leeds station where it was along the corridor from the TCS / Signing On Point, or a small place like Selby where there is a small mess room in one of the station buildings but no signing on point or supervisory staff located at all.  In BR days it was normal for guards' machines to be given out and paid into the Travel Centre / Booking Office (in may places they still are) in those places the word "Lobby" could refer to the paying in window at the back of the travel centre where this took place.

  • Like 3
  • Informative/Useful 1
Link to post
Share on other sites

  • RMweb Gold

As far as I'm aware the term "Bothy" is of Scottish origin meaning hut or cottage, I'm not sure but it might also be in use in Wales, and has little to do with railways apart from as a generic term for small building of rudimentary design. It's used a lot in the mountain rescue fraternity. It's use in the aforementioned fog and falling snow ditty is just a local colloquialism. As the insewing posts have illustrated each area of the country substitute its own colloquial term for hut.     

Regards Lez.  

  • Like 3
Link to post
Share on other sites

  • RMweb Premium

Thanks to expert carpentry assistance and advice earlier in the week from @Mallard60022, the baseboard has been extended by a couple of inches, which makes all the difference and means Four Road is now a safe distance from the baseboard edge.  The train crew building has taken flight again and is now on the other side of 4 Road; whether it stays there (or stays anywhere) remains to be seen.

 

IMG_3100.jpg.636e1b3bfa1f696ee24ed9bf9932e523.jpg

 

This picture shows the Peco turntable installed; I've added a platform at the near end for the vacuum motor controls, but won't put these or the handrails on yet until after I've done more testing.

 

IMG_3102.jpg.9a333b492e28c1e38070d76c2775e153.jpg

 

Three and Four Roads will need buffer stops of some sort; getting the turntable to line itself up with more than two roads might be a step too far!  Also, I'll need to extend the road bridge abutment, and the advertising hoarding may have to go.

 

  • Like 17
  • Craftsmanship/clever 1
Link to post
Share on other sites

  • RMweb Premium
4 hours ago, 31A said:

Thanks to expert carpentry assistance and advice earlier in the week from @Mallard60022, the baseboard has been extended by a couple of inches, which makes all the difference and means Four Road is now a safe distance from the baseboard edge.  The train crew building has taken flight again and is now on the other side of 4 Road; whether it stays there (or stays anywhere) remains to be seen.

 

IMG_3100.jpg.636e1b3bfa1f696ee24ed9bf9932e523.jpg

 

This picture shows the Peco turntable installed; I've added a platform at the near end for the vacuum motor controls, but won't put these or the handrails on yet until after I've done more testing.

 

IMG_3102.jpg.9a333b492e28c1e38070d76c2775e153.jpg

 

Three and Four Roads will need buffer stops of some sort; getting the turntable to line itself up with more than two roads might be a step too far!  Also, I'll need to extend the road bridge abutment, and the advertising hoarding may have to go.

 

Ref the woodwork.....my pleasure matey. Glad I actually could keep upright and awake for enough time to guide you with this.

Guys and gals, what 31A has not showed you yet is his amazing wiring diagram for the planned control of this area. Something I could never do. There is even the switch/track layout diagram unit ready to fit. It has been my pleasure to assist 31A with this project in a few small ways and I am sure it is going to enhance his enjoyment of what is already a great layout.

I can confirm that the TT is superbly weathered and works beautifully and prototypically...…...and that 4 'typical' nasal decongestant covers (the cylindrical type with a single domed end) will be the correct item for creating the Vac Cylinders. Buy 4, ditch the inner decon' bits (or sniff freely for fun), take the 4 cylinders, cut the domed end off 2 and fit carefully to the open end of the remaining two and lo, you have two suitable shaped items.

A. Sniffer.

  • Like 4
  • Thanks 1
  • Informative/Useful 2
  • Friendly/supportive 2
Link to post
Share on other sites

On 26/11/2019 at 15:07, 31A said:

I've spent the last few weeks working out how to motorise the turntable.  To be honest, I was slightly underwhelmed by the new Peco turntable motor; as it's turned out not to have an indexing feature and relies on lining the rails up by eye, I thought it was quite a lot of money for what it was.  I'd used Meccano to drive a Peco turntable on a previous layout (albeit that also relied on lining up the rails by eye) and having a box full of it for about the last 50 years I thought I'd see what could be done with it.

 

One thing that has often struck me about model turntables is that the motion can be jerky in a way that isn't possible when 100 tons of loco is being turned.  Also if possible I wanted the table to stop automatically when in line with the rails feeing it.  I thought flywheels would be a way to eliminate jerky motion and indeed they were, but they imparted so much inertia that it was impossible to stop the table in line with the rails!  The real one at the NRM seems to have the same problem, when it is being demonstrated.  So I've come up with a mechanism that disengages the drive at the same time as the current is cut, and the lock drops in.  That way, the flywheels can carry on rotating until their energy is dissipated, whilst no longer turning the table.

 

Here are a few pictures of it.  The description may sound like an article from "Meccano Magazine", as I will try and use part descriptions from the catalogue, although "Microswitch" wasn't in the Meccano vocabulary, and "jam jar lid" didn't feature often either.

 

The first picture shows the "control" side.  The motor, which is from an old tape recorder, drives Shaft A.  The blue Pulley is one of the flywheels, and behind it is a 1/2" Pinion which engages with a 1 1/2" Gear Wheel on Shaft B, which also carries a Worm.  Shaft C is the "Control Rod", with the Control Lever on the end - on the layout this is much longer and comes out to the front of the baseboard.  Among other things, turning this operates the micro switch which energises the motor.   On the finished version, the turntable itself is attached to the top of Shaft D.  As can be seen, at the bottom of this shaft is a 3 1/2" Gear Wheel, with a jam jar lid attached to it.

 

The ends of the green girders at the top are attached to wooden blocks under the baseboard, either side of the Peco turntable well.

 

IMG_3091.jpg.bab359db31bcc1a6588d9fb4b88630cd.jpg

 

The next picture shows the "drive" side.  The motor drives by belt a 1" Pulley, which is behind the other flywheel.  Originally I used bigger pulleys as flywheels, but they caused a lot of vibration - they were probably no longer true!  In this picture you can see the "Follower" (E) and the Tension Spring (F) which causes the Control Rod to drop when the Follower reaches a notch in the side of the jam jar lid, which corresponds with the position of the rails on the baseboard.  When this picture was taken, I was just testing that the table could be made to stop accurately enough after turning 180 degrees; to do this there are two notches in the side of the jam jar lid, which obviously must be exactly opposite each other.  On the layout, the table will serve two roads, and there are now additional notches to cater for this.

 

IMG_3095.jpg.785fe0304dd4f38b280fc3e2420e1cb4.jpg

 

 

Next is a close up of the jam jar lid and Follower.  The Follower rises and falls in the slot made from a 3" Formed Slotted Strip - as supplied these are curved, but this one has been straightened and then bent though 90 degrees so that the slot is vertical.  This eliminates any side play in the follower, when it has dropped into the notch in the jam jar lid, and holds the table tightly in place.  The follower is carried in a 1 1/2" Double Angle Strip, which is attached to a 1 3/8" Bushed Wheel on the end of the Locking Rod.

 

IMG_3096.jpg.649fc33374fffb4195eca68017636cf8.jpg

 

The last picture shows how it works!  The Control Rod carries a Coupling (G) which holds a Threaded Pin, the other end of which engages in one hole of a Fork Piece on the Locking Rod.  Moving the Control Lever clockwise causes the Fork Piece to lift the Locking Rod.  This lifts the Follower (I) out of the notch in the jam jar lid and activates the microswitch which starts the motor.  Crucially, it also lifts the 1 1/2" Gear (H) as this is on a Rod with Keyway, meaning it can slide up and down whilst still turning the rod.  Lifting this gear engages it with the Worm on Shaft B and causes the Final Drive Shaft D to rotate.  Once the table has started rotating, the operator can let go of the Control Lever because the Follower runs on the rim of the jam jar lid, holding the Locking Rod up which keeps Gear H in mesh and the microswitch closed, until it reaches the next notch in the jar lid, when it drops, cutting the power, dropping Gear H out of mesh, and locking the table in place.

 

IMG_3097.jpg.0ba89ec56d26f05bf0a50999a592c48c.jpg

 

Quite a lot of experimentation was necessary to get this all to work, and several elements needed careful adjustment but it has now been installed and tested on the layout, and so far (touch wood) is working quite reliably.

 

For the moment it is temporarily fed directly from a 6v DC supply, but when I make the control panel for the Loco Yard I will pass the motor feed through the track section feed switch for the turntable rails so that a loco can't be driven whilst the turntable is rotating, and vice versa.  At the moment it only rotates anticlockwise but I will also incorporate centre off DPDT switch to reverse the polarity of the turntable feed so that it can rotate in either direction, with the centre being an "Emergency Stop" switch; something which is sadly lacking at the moment!

 

 

 

good grief, man.  couldn't you just push it round with your fingers, all the while making suitable turntable noises?

 

:)

  • Funny 7
Link to post
Share on other sites

  • RMweb Premium
3 minutes ago, Dr Gerbil-Fritters said:

 

good grief, man.  couldn't you just push it round with your fingers, all the while making suitable turntable noises?

 

:)

 

Where's the fun in that?  :jester:

  • Like 2
  • Informative/Useful 1
  • Funny 1
Link to post
Share on other sites

  • RMweb Premium
1 hour ago, Mallard60022 said:

Ref the woodwork.....my pleasure matey. Glad I actually could keep upright and awake for enough time to guide you with this.

Guys and gals, what 31A has not showed you yet is his amazing wiring diagram for the planned control of this area. Something I could never do. There is even the switch/track layout diagram unit ready to fit. It has been my pleasure to assist 31A with this project in a few small ways and I am sure it is going to enhance his enjoyment of what is already a great layout.

I can confirm that the TT is superbly weathered and works beautifully and prototypically...…...and that 4 'typical' nasal decongestant covers (the cylindrical type with a single domed end) will be the correct item for creating the Vac Cylinders. Buy 4, ditch the inner decon' bits (or sniff freely for fun), take the 4 cylinders, cut the domed end off 2 and fit carefully to the open end of the remaining two and lo, you have two suitable shaped items.

A. Sniffer.

 

Please visit again soon, when you've finished sniffing and don't forget to bring the nasal decongestant covers!

 

  • Funny 3
Link to post
Share on other sites

  • RMweb Premium
7 hours ago, 31A said:

Thanks to expert carpentry assistance and advice earlier in the week from @Mallard60022, the baseboard has been extended by a couple of inches, which makes all the difference and means Four Road is now a safe distance from the baseboard edge.  The train crew building has taken flight again and is now on the other side of 4 Road; whether it stays there (or stays anywhere) remains to be seen.

 

IMG_3100.jpg.636e1b3bfa1f696ee24ed9bf9932e523.jpg

 

This picture shows the Peco turntable installed; I've added a platform at the near end for the vacuum motor controls, but won't put these or the handrails on yet until after I've done more testing.

 

IMG_3102.jpg.9a333b492e28c1e38070d76c2775e153.jpg

 

Three and Four Roads will need buffer stops of some sort; getting the turntable to line itself up with more than two roads might be a step too far!  Also, I'll need to extend the road bridge abutment, and the advertising hoarding may have to go.

 

Jolly good things, these baseboard extensions. That's a lovely job altogether Steve.

  • Like 1
  • Thanks 1
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...