I have been working on the branch milk train as part of the sequence for Tinworthy.
The make up is based on a picture of the branch milk train from Launceston to Plymouth where the milk tanks would have been added to others from various places along the line from Penzance to make up the long milk train for London.
It seems a while since I posted about Tinworthy despite all the time I’ve had on my hands during lockdown.
I have been starting to develop the scenery around the station and have been initially concentrating on the goods yard, entrance roadway and the loading bank mainly used for loading pit props into wagons.
I have included some half relief cottages, a copse of trees and the start of a painted backscene. This end of the layout doesn’t follow the prototype Tavistock out of necessity to have a raised portion of scenery to disguise the point motors therein. Hence the thatched cottage which is now on its third layout!!
My plan is to gradually move along the layout with the scenery. This means having to build the signal box, motor shed and stables.
I haven’t posted much recently but that doesn’t mean I’ve not been active.
Firstly I have built the footbridge which spans the two platforms between the end of the station and the goods shed.
It is constructed from Plastikard and is interesting in that the supports on the up platform end span the stone wall which goes along the back of the platform. The wall is still to be painted and weathered as well as the platform surfaces.
Secondly I have finished an LSWR A12 Jubilee from a 3mm Jidenco etched brass kit. This forms a Southern branch train diverted through Tinworthy due to problems on the Southern Railway line.
The loco is finished as one of the last of the class which survived just into nationalisation. It was allocated a new number but never carried it, being withdrawn for scrapping in December 1948.
Finally, I have converted a 57XX built for 12mm gauge to 14.2. The chassis was one built by the late Rodney Pearce and has a Portescap motor whilst the body is a GEM whitemetal converted to the later Collett style. I acquired this many years ago and have no idea who originally built it!
The model is finished as 3686 which was one of the panniers shedded at Laira shed in Plymouth. It is seen on a short pick up goods. The loco is awaiting some weathering.
Having finished the main station building my thoughts have now turned to the main goods shed. As with the station a reduction in space has of necessity meant a proportional reduction in the size of the goods shed while at the same time trying to preserve the feeling of the original. Tavistock had quite a sizeable goods shed with two tracks running through it. It was of a timber construction with a brick built office at one end and a wooden lean to office at the other end.
I used a plan of Chipping Campden shed from Ian Allan’s book on Great Western Branch Stations to get general dimensions and pictures of the original Tavistock structure to get a suitable representation. The model is constructed from card. Unfortunately the card I used for the main roof is a bit thin which resulted in some bowing which I managed to reduce to a degree by using internal bracing. Hopefully it doesn’t show too much.
The shed has now been installed and the water tower and Down starting signal as well. The water tower is a cut down version of a typical GWR conical tower. This was originally a 3mm Society kit and is recycled from an old layout of many years ago!
The final part of this end of the station will be a covered footbridge which sits between the station and the goods shed and connects the two platforms. This is the next project…..
The original Tavistock GWR station had an overall roof. My interpretation of the station for necessity of space involves a shortened building. There are no plans of the original station but looking at pictures in a very good article published in the Great Western Journal I could see comparisons with the buildings of Henley-on-Thames. They are in brick whereas Tavistock is in stone but the window and door sizes appear quite comparable. There are very good drawings of Henley in Paul Karau’s book on the subject.
The building Is constructed from card to which I stuck a brown manilla envelope turned inside out onto which I scribed the stone courses. This is a method I learnt from the late Peter Gentle-a superb building modeller. The brown paper gives a very good texture and takes watercolour very well. The stones are painted on using various shades of grey and brown
The outer wall of the train shed is constructed from a sandwich of Wills sheets and planked plasticard with the windows made up from thin card and set into openings cut in the sheets.
The overall roof is made from mounting board with plastruct girders and trusses soldered up from 0.7mm brass rod on a marked out jig. The outer surface is covered with corrugated plasticard. The whole roof is detachable to allow access to the inside of the shed.
I think it portrays an atmosphere of the original building.
In lockdown again but there still seems to be multiple jobs to keep me away from the modelling room!
However, there has been some progress. The track has all been ballasted and painted, the platform basics are in place and I have started on the station building and overall roof.
Initially the track and cork base was airbrushed with a mixture of grey and earth colour. I use the Vallejo paints which are already thinned for spraying.
The ballast is then added dry and gently brushed into place. I use Attwood Aggregates ex fine ballast which is produced local to me.
The ballast was then fixed in place using a PVA based laminate floor polish. I originally found out about this method from a thread on the Scalefour forum. The original polish was Johnson Klear but this is no longer available. However I found an equivalent from B&Q made by Stickatack.
Using a pipette the polish is dribbled along the edge of the ballast and immediately is ‘sucked’ across without disturbing the ballast. It dries far quicker than the messy method of using diluted PVA and is much easier to remove if necessary.
For the areas between the tracks I used very fine, almost dust, granite chippings mixed with grey weathering powder applied to ordinary PVA brushed on. Finally the whole lot was airbrushed again with a rust coloured paint and some black over the areas in the platform where locos would stand.
Three signals and two points on Tinworthy are driven by servos. When first installed two signals and a point had digital servos and the third signal and one point had analogue servos. All the servos are driven by Heathcote servo driver boards via relays switched by the MERG CBUS system.
I found that the two analogue servos ‘twitched’ when a loco was driven past but not the digital ones. According to the Heathcote web site, they recommend digital servos as they do not twitch at startup.
I am not an electrical expert but I understand that the amount the servo moves is determined by the control pulse coming from the control board which has controls to determine the start and end points of travel of the servo. However there appears to be a degree of overthrow before the servo cuts out and the position is then maintained by the gearing in the motor. This is fine when working a signal but with a point the end point needs to be set so that the point blade is hard up against the stock rail (which is why in the prototype there is a facing point lock) and therefore the digital servo is continually trying to reach the cut off position and the result is ‘chattering’ of the servo. This doesn’t happen with analogue ones. If the throw of the servo is adjusted so the point blade only just reaches the stock rail then the chatter is eliminated but there is the risk of trains derailing because the blade is not ‘locked’ in place.
So do I twitch or do I chatter!
Recent postings on the forum of MERG suggested that by using omega loops or ‘Z’ loops the chattering of a digital servo can be eliminated and the loop keeps up the pressure of the point blade on the stock rail. I have tried this and it has solved the problem.