Thursday, 1 April 2021

Mechanical Interlocking Completed!


Mechanical interlocking completed 

1st April 2021

It has been a very interesting part of the overall project this one. I now have a big appreciation for what the locking fitters of old and current do. First of all the planning of the work, then doing the work. There is very little room for error when creating the locking bars as well as the cutting of the notches in the tappets. Then trying to fit the locking bars in the channels, some of the locking bars designed to fit under the tappets and the others on top of the tappets. It has been a very challenging job indeed.

This is how we were looking at the end of the weeks work, the stop board removed from the end of the up platform and the new DN starter on the up platform brought into use as it is solely controlled by the mechanical interlocking. 4 7 16 still require the electrical interlocking to be completed before being brought in to full use.

This is a look at one of the newly made locking bars. This one is for insuring that 2 points are set for the main line and that 3 FPL is reverse. Only then can 16 signal be pulled or 12 the King lever for locking out the signal box. This is for single line working from Aviemore to Broomhill.

This is one of the existing locking bars that had to be modified. Before it was 8 signal locked 19 points. Now that it has been changed it is 8 signal locks 17 signal and 19 points. There is a second bar that locks 8 signal to 18 FPL.

This is the before and after of cutting the notch on 2’s tappet. The lock piece is used to give the size of the notch that needs to be cut. This notch is for the locking bar between 2 and 7 signal insuring that 2 points are normal before 7 signal can be pulled. 

Once all the new and modified locking bars and the tappets with there notches cut in the correct positions. This is how both the top and bottom locking boxes were looking. In my opinion it is one of the most important parts when it comes to signalling. With out it, it would be almost impossible to run the trains safely.

This next little video is NOT the full locking test but it gives you a feel to how much goes into this. A full independent interlocking test was done after this video was shot, by a college who was not involved in the work. The mechanical interlocking was found to be working correctly and fit for purpose.

This is a very big step forwards. Next we will be moving onto the electrical interlocking. This is required to supplement the mechanical interlocking to insure that safety is maintained.

Tuesday, 23 March 2021

Boat of Garten North Interlocking

 Boat of Garten North Interlocking 

21 March 2021

It has been a while since the last update, progress has been slow with the forever changing situations. Anyway progress has been made! A lot of time has been spent making up drawings to work from, in regards to the interlocking. It has taken a lot of drafts, emails and discussions with colleagues but in the end I believe we have a working plan for the interlocking for the north signal box. 

For those who do not know or understand what “interlocking” is. Basically it is what determines if the train can be signalled from signal A to signal B. I suppose you can call it a mechanical computer, only if the levers are in the correct position and have been pulled in the correct order will you be able to pull off the signal allowing the train to move.

Just a reminder for us all this is what we are working towards. Still lot’s to do but it will be good when it is all finished. 

This may not look like much but a lot of time and effort has gone into this, by several people! Each picture is one locking box. This is the diagram of what needs to be done to allow train’s to run safely preventing any conflicting movements and ensuring that the signaller can only do his job correctly.

We have been lucky to find some locking tappets in one of our store vans. Which have had the old notches cut off and new metal bar added, so they are as good as new! Other than needing cleaned and polished up they are ready for use. Thank you who ever took the time to do all this work in the past, it is much appreciated.

This is how we were looking after a day had been spent cleaning up the tappets. At this point the pins still needed cleaned up and pin holes skimmed out. This was all completed and they were taken back to the signal box at Boat Of Garten to be trial fitted.

With out the new tappets in, this is how the locking looks in the locking boxes. So what you can see in the top locking box is two channels for the locks to sit in. Thus allowing you to have up to four locks on one tappet if required. You can just make out the “locks” the “tappets” and the bars that hold it all together. It’s not the easiest to get a picture of because of its location and certainly not the easiest to work on.

Not the easiest thing to show in a picture but this is all the tappets that we require in the locking boxes. The locking boxes are of a Eastern Region design, on our Mackenzie and Holland frame. This was quite a common thing with the frames that had been sent to Crew to be serviced and prepared for the next signal box that it would be installed in.  The tappets are not straight, there is a curve half way along them because of the way the lever moves in the frame. Each tappet in turn needed to be shaped as required for a smooth movement from the normal to reverse position. After a lot of removing, shaping and replacing this was finally achieved.

With the tappets all in the locking boxes sitting ready for the notches to be cut to take the locks. It was time to start looking at making up the locking bars. Hear you can see a selection of the different shape locks and the bars that hold them all together. This is what prevents or allows the levers to be moved.

This is the first attempt of riveting the dies to the bars, not a bad attempt a lot has been learned and will see about doing it for real next time.

Saturday, 2 January 2021

Early December, Lighting testing.

 Lighting testing, 

For the short time that we were able to run trains for this Christmas period, Maintenance checks was carried out on all signal lighting circuits, before the Christmas running season began. It sounds an unimportant job, but when that light is the only way for the driver to know when it is safe to go or must stop. Then they are quite important in the winter mouths with low light levels and snow conditions. Our signal lights are well above the standard that is required for signal lighting and are all LED lit, I believe that the Aviemore South bound signal light can be seen from 3/4 a mile away! So more than adequate for braking distances.

Selection on Boat of Garten signals being checked all with LED lights.

Out with the old and in with the new, wiring!

 2nd January,

Out with the old and in with the new! 

That’s the wiring I am on about. Things have slowed down with the Boat Of Garten North project I am afraid. The next steps are requiring a lot of drawings and off site work to be done first. The likes of interlocking requires to be planed and drawn up and discussed before work can be commenced. So for the time being with current government restrictions and our own restrictions this will need to wait until it is deemed safe to travel and Spey lodge is available for use by our members. In the meantime, work on creating a cable route, to hide all the unsightly cables can be created. Work has also started on the mounting of the power supplies. The power supplies are for feeding out to the line side locations, to feed track circuits and indication circuits. Signal lightning supplies and the lever locks under the signal box. This has been slowed down as it was not known that all the 1960 BR cabling was still in place. This all had to be removed before removing and repurposing the old wood cable routes to suite what we are requiring. All very fun, dusty and dirty work!

The old BR wiring being removed, in surprisingly good condition for its age.

New power supplies transform boxes been placed, transformers are not in the boxes yet that’s another days job. The New, Old cable routing going into place to carry the power supply cables, and round to the lever locks attached to the lever frame and up through the floor to the relay cabinet on the operating floor.