Purpose A marshalling yard is for sorting wagons which arrive from many sources and need to be moved from one train to another to continue their journey. These yards are typically placed outside of towns where there is plenty of space, near national network junctions and junctions with local branch lines. Prototype yards are quite dense but sprawling whether very early flat or what was increasingly common in the UK, gravity or hump yards. In a hump yard newly arrived wagons were uncoupled into cuts (groups of commonly destined wagons) and pushed slowly over a hump. They were then allowed to roll down the other side where their speed and destination was originally controlled by men on the ground operating the wagon brakes with poles and operating the points. This was a dangerous and an easily fatal occupation, but as the decades passed mechanical retarders, and later still speed boosters were added. Control tower operation of points, retarders and boosters with increasing computerised control would then keep most men out of harm’s way. How to Implement? A gravity yard is not realistically viable in 1:76 as vehicle inertia, friction and available space make creation of an operational yard very difficult to implement. The differing mass and friction properties of models are so diverse and inconsistent much work is required to ensure that all wagons perform consistently to one another. Even prototype wagon sorting eventually used radar for wagon speed detection, primary and secondary retarders and speed boosting, computer controlled as required. I'm certainly not going to model that! The pure dynamics alone are a problem, a model at 1:76 scale has 1/76x76x76 (or 1/438976) of the mass of a full size wagon, and the slopes would only be for 1:76 of the distance, modelers of flying models and sailing boats have similar issues when proportioning scale models to actually fly or be wind blown by sail. Friction is also a problem, 1:76 models rarely need operating brakes to stop them rolling, a full size wagon can probably roll away out of control on 1 in 200 slopes, many of our models are unlikely to roll on 1 in 100, and some of mine on 1 in 50! It was proposed by BR for later yards the arrival (or reception) roads would be in a basin so the wagon brakes would not need to be applied, to speed up the handling of wagons during shunting and hump sorting, no need for that in a 1:76 model. So Warren Yard is flat, no transfer of goods is made between rail and road so the sidings are close together, only shunters (men coupling and uncoupling wagons) and yardmen marking up the wagons would need access, traders, public and even train crew were not permitted. Really the physical layout of Warren Yard echoes ancient history, but also ironically the state of some hump yards that were partially decommissioned as rail traffic declined. In particular in the industrial heartlands of coal and steel in the UK where the hump tracks were lifted and the sorting sidings became flat shunted sidings, e.g. the Tees yard in 1983 (Ref 2.1). Track Layout Typically high throughput yards would be unidirectional, smaller ones bidirectional. I did not have the space for 2 yards, certainly the throughput on my yard would not warrant up and down yards! I examined it on paper but then there would have been no space for the branch industries and docks, so I settled for one bidirectional yard as I wanted to pass traffic both ways between the branch lines and the national trunk route. The next image shows only the trackwork for marshalling activities and the connection to the national trunk line. It illustrates how I have managed to integrate key marshalling yard functionality, layout and connections between the trunk line and two branchlines to be a viable and operationally interesting core to my railway layout. Many iterations where examined with the AnyRail CAD tool before any track was laid, subsequent tweaks are similarly tried with AnyRail before lifting and reworking track layouts. During the design phase it is very important to define the lengths of your trains so that each part of the railway works as a 'team' so to speak, arrival/departure roads and fiddle yards being the highest priority to match up, failure to do this results in failure to operate. Maximum train lengths were set as :- 1) Mainline - 6 coaches or equivalent rake of wagons, plus loco 2) Branch/local 4-5 smaller coaches or equivalent wagons, plus loco Engineering is the art of compromise, this applies as much to models as to real life. Please Note: My description of the operation of Warren Yard is different to any prototype because it is not laid out like any prototype. I attempt to replicate how prototypical practices may apply and this is how I approximate to it in my miniature world, (Rule 1 again). Arrival & Departure Roads Warren yard has two bidirectional roads where trains arrive at the yard for partial or complete dismantling. These roads have signals at each end that are for releasing trains onto the trunk line of the national network or the branch lines. I discuss signalling in the next article. National network trains are normally just passing by only stopping to drop or pickup wagons. The branch line locos operate on the branches only and work between the industrial and dock yards and the marshalling yard. So they drop their entire train in the arrival road for sorting and mostly subsequent collection by national network trains. They may return on the branch with wagons destined for the local industry and docks from the national network straight away or return to the yards loco services whilst awaiting their next turn. Some branch-branch traffic is also sorted here, e.g. imports from the Euroferry port or the heavy minerals dock and exports from the Minix Motor Works to the Euroferry port. When a train of wagons arrives they are inspected by the head shunter, wagon dockets checked and wagons chalked with destination sidings. They also physically inspected for issues such as hot boxes, brake gear problems, body damage or shifted loads, those that need immediate attention are marked with a red card for transferring to the wagon repair works for repair before returning to use. The repair may be sufficient to subsequently raise it to green card status to allow it to make one further journey. Wagons with lesser issues may continue for one more run will be green carded which applies particularly to loaded and specialist wagons e.g. tank wagons returning to the fleet owner. As I understand it the tank body is owned and maintained by the fleet owner and the chassis by BR so it would depend on the nature of the problem to who repairs it. If loaded and repairs cannot be easily performed then the loads are transferred to another wagon from the seasonal and spares store in the PW yard. Specialist wagons that are to be returned to the fleet owner for repairs will be held subject to contact with the owners. This would typically apply to tank wagons and any hazardous load wagons. I acknowledge the carding information was made known to me by P1MRC member Echidna. Further information may be found about prototype yard practice in Ref 2.2, where Echidna describes activities from his professional days working on the railways. Sorting Roads Wagons for sorting are removed from the train, they should have been grouped together by each yard that dispatched them and will consist of loaded and empty wagons. They are then shunted into the sorting roads according to the markings applied by the head shunter, each road is allocated one or more destinations. The Warren Yard road allocation is shown below. As can be seen some destinations are national whilst others are local such as docks and industry, being close to the east coast there is no national network route to the east, only local. In the images below some examples of sorted trains can be identified, road 1 is nearest to the trunk line. 1) Road 1 - A rake of empty mineral wagons required at another yard north of here. 2) Road 3 - Contains an empty Esso tank wagon and two Traffic Services (latter returned from the Euroferry port) for delivery west of here. 3) Road 4 - A vehicle export group of wagons from the Minix Motor works, 4x TIERWAGs of saloon cars, 4x LOWFITs containing vans and 3x ex-GWR MOGO wagons containing spares and accessories await collection for delivery to the Euroferry port. A shiny new Class 07 is being evaluated by the yard crew. 4) Road 5 - Miscellaneous open wagons to be taken to the docks for unloading a tramp steamer that is due shortly. 5) Road 8 - Empty coal wagons to be taken to the Tattyedd Colliery If the train that has arrived is to take away wagons they are fetched from the sorting roads and attached to it, when that operation is complete it is cleared to leave the yard. At intervals wagons for delivery on the branches are collected from the sorting roads and delivered to their branch destinations. Model notes. As can be seen I mix vintage and current rolling stock freely, the differing coupling types will hang together well enough for shunting but will be arranged with suitably fitted locos or insertion of one of many coupling convertor wagons I have to hand before leaving the yard. The TIERWAGs are fitted with Romford 10.5mm disc wheels and the tinplate mineral wagons and Dublo tankers with current Bachmann or Hornby wheels on silver steel axles. (N.B. Annoyingly, just re-wheeling a 3R guards van only to find the Hornby 3 hole disc wheels seat on splines now, this results in a loose rather than push-fit onto replacement 2mm silver steel axles , okay, back to Bachmann whose quality has not been outstanding in recent years ). Continued below ...
Continued from above. Brake Vans Two short sidings are provided, one at each end of the sorting sidings for surplus brake vans and parking yard shunters, which also have a siding reserved in the loco services area. The northern siding at this time contains a gangers Wickhams trolley, a brake van and a Class 03 shunter. Bypass A bypass road links the loco services to the PW yard and wagon repair works which avoids conflicting with arriving and departing trains, this is also used to run locos around their trains for the return trip and also allow them access to the turntable and other loco services. Head shunt A limited head shunt allows moving wagons between the sorting and arrival/departure roads, it is also used to access the loco services. Not as long as I would have liked as it can only handle half an arrival or departure train of wagons at a time so increases the amount of thought required to shunt the wagons. If the head shunt was extended far enough it would have breached the scenic break at that end of the of the marshalling yard which I was less than enthusiastic about. I consider scenic breaks as very important (Ref 2.3). Summary Having presented why I have designed and built it the way it is and described it's intended operation I will follow up with the approach I have taken to signal access to this yard, an approach which I have expanded across the layout as a whole in an attempt for consistency. Development of the ancillary services i.e. the loco services, PW yard and the wagon repair works will be presented in further articles. Thanks to P1MRC member Echidna for comment and extra information. References: 2.1 The Illustrated history of British Marshalling Yards Author: Michael Rhodes, Publisher: Haynes Publishing Group, 1988 2.2 Realising a Dream - 20 - Laying the Track Replies by P1MRC member Echidna on yard practices. https://platform1mrc.com/p1mrc/index.php?threads/realising-a-dream-20-laying-the-track.5843/ 2.3 Scenic Breaks - Realising a Dream - 4 - How Do I? Importance of scenic breaks. https://platform1mrc.com/p1mrc/index.php?threads/realising-a-dream-4-how-do-i.5533/ Next, Signalling Discussion always Jim Return to Index
