Saturday, February 24, 2018

Murrbahn in HO: Trackplan version 0.5-0

Main Level
In this updated version of the track plan I tried to address short-comings of the previous version.

Not much changed on the main level. I straightened out the curve on the left of Backnang station and am now going through the closet wall. I also locked down the space for industrial area, matching the area of the Untergroeningen station above it.

Thinking through traffic patterns and how engine changes will work, I think I need to flip direction assignments of tracks 3 and 4 to better match the track work on the right-hand side of the station. In Backnang many trains changed power from steam- to electric-powered locomotives. The problem is that currently there is no efficient way for a waiting engine on track 7 to get to a Stuttgart-bound train standing on track 4.  If Stuttgart-bound trains arrived on track 3, the steam locomotive can uncouple and pull forward to the cross-over near the West-end of the storage tracks and head back to the turntable via track 5, while an electric waiting in track 7 couples to the train and continues the journey as soon as the steamer is out of the way. The drawback of doing this: west-bound and east-bound trains need to cross paths before leaving station limits, creating a bottleneck. Hmmm. That's not good either.
Alternatively, I could swap mainline track 3 where it parallels track 7 with track 7 and add a crossover to track 4, so that the waiting track is between the two mainline tracks. However, that requires changes to how the storage tracks connect to track 7, resulting in significant reduction in length. Oh well, I have some time to mull this over. This station won't be built for quite a while.

Upper Deck
Several changes in Gaildorf/West and Untergroeningen on the upper level.

The weg branch is famous for the wood chip cars going to the sawmill in Unterrot. Since I don't have enough space to model Unterrot, I replaced the non-prototypical Raiffeisen spur with a track that leads to the sawmill. The sawmill will be represented on the backdrop only. There's not enough space here to model this rather expansive industry, so a fence and a couple signs will need to suffice.

Pretty early on in the planning phase I chopped down the yard in Gaildorf/West again due to space constraints. I cleaned up the tracks to allow for more effective use of what's left, at the cost of moving further away from the prototype. I do think that's a good trade-off, though.

Staging below main level
Most of the work in this iteration went into staging. I replaced the 7 through tracks and 7 stub tracks in the previous plan with 13 through tracks and 6 stub tracks. Contrary to the previous plan staging tracks now have varying lengths, with most tracks comfortably fitting maximum-length trains. The stub tracks moved under the Untergroeningen pensinsula.

To make the plan easier to understand, I color-coded the various areas. The double-track main line coming from Backnang is shown in brown. The tracks enter the tunnel to staging above the return loop on the left of the room and follow the walls around the room to the cross-overs on the right-hand side of the room. This ramp is about 9m long, so with a steady grade of 2.0% I get 20-25cm deck separation for staging. In the lower right corner the helix comes down from Gaildorf/West on the inside track, and Backnang via "Kleine Murrbahn" on the outside track.

The staging tracks are accessed via the yellow loop track. Coming out of the cross-overs, the loop track runs next to the mainline ramp at the rear of staging going around the green through tracks. Trains can be parked in the purple staging tracks facing left. To get to the green staging tracks, a train continues on the yellow track through the closet wall and the return loop. In green staging, trains are parked facing right. To leave staging, a train from purple staging exits its assigned track to the left, through the return loop and on the yellow track along the aisle to the cross-overs at the bottom of the ramp. From green staging tracks the train exits right into the cross-overs.

The teal stub-ended staging tracks are accessed similarly using the yellow loop track.

A train leaving or entering staging can enter the layout to any direction and vice versa.

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