30-09-2015, 03:16 AM
PJW sent me an email with a link to this thread this evening - a nice surprise before a night shift!
If the site were laid out to LU practice I would not expect to see anything other than a reduced overlap on 119 signal with 105 signal requiring either 119 'off' or a timing section on the approach to 105 to validate the reduced O/L.
However, in terms of answering the questions as asked, I would expect the controls of 105 to include up to and including CH and mechnical locking to be 105 x 214.215
However I would then expect the overlap locking to be 'handed over' to 119, with the backlock controls being 105G and V 'on', and (CF occ, 119 ®) or (CF occ. CG clr for 15 seconds).
The second question relating to 119C © is somewhat harder to replicate in the LU world - as LU hasn't coupled on the main lines since the 1970s.
I would deliberately omit DA from the controls (this being the 4-car portion the second train is due to couple to) and likewise omit all the proving of the TETS trainstops and their associated timers (assuming that these would be operated by the first train already berthed in the platform). I would additionally expect a train at 119G to be proved not only at rest but also to be a short train suitable for coupling.
In terms of the mechanical locking, I do feel that 119 is somewhat complicated to mechanically lock quickly (It's 3am) and in reality would require some conditioning. Rather than looking directly at the lever locking I would first just list conflicting routes which must be normal. The three traditional non-vital circuit levels used by LU do this - in particular the UR which is used to feed lever motors. Before the UR is allowed to pick all conflicting URs must be down - which in itself is a form of non-vital locking between different routes at route level.
One observation I do have is that I think there is too much reliance based on the technology used by listing relay names and their positions, amking the control tables look more like circuits expressed in tabular format rather than tables of controls.
For example '200 VCR up'; why not 200V 'on' and in the Approach lock, how about '105 signal and trainstop on and CB clr'?
If the site were laid out to LU practice I would not expect to see anything other than a reduced overlap on 119 signal with 105 signal requiring either 119 'off' or a timing section on the approach to 105 to validate the reduced O/L.
However, in terms of answering the questions as asked, I would expect the controls of 105 to include up to and including CH and mechnical locking to be 105 x 214.215
However I would then expect the overlap locking to be 'handed over' to 119, with the backlock controls being 105G and V 'on', and (CF occ, 119 ®) or (CF occ. CG clr for 15 seconds).
The second question relating to 119C © is somewhat harder to replicate in the LU world - as LU hasn't coupled on the main lines since the 1970s.
I would deliberately omit DA from the controls (this being the 4-car portion the second train is due to couple to) and likewise omit all the proving of the TETS trainstops and their associated timers (assuming that these would be operated by the first train already berthed in the platform). I would additionally expect a train at 119G to be proved not only at rest but also to be a short train suitable for coupling.
In terms of the mechanical locking, I do feel that 119 is somewhat complicated to mechanically lock quickly (It's 3am) and in reality would require some conditioning. Rather than looking directly at the lever locking I would first just list conflicting routes which must be normal. The three traditional non-vital circuit levels used by LU do this - in particular the UR which is used to feed lever motors. Before the UR is allowed to pick all conflicting URs must be down - which in itself is a form of non-vital locking between different routes at route level.
One observation I do have is that I think there is too much reliance based on the technology used by listing relay names and their positions, amking the control tables look more like circuits expressed in tabular format rather than tables of controls.
For example '200 VCR up'; why not 200V 'on' and in the Approach lock, how about '105 signal and trainstop on and CB clr'?