Going Uphill – Part 1

This week I’d planned on bringing you some more 3D printed gears but the delivery’s been delayed so I haven’t received them yet.  So instead I thought I’d share with you my latest creation for our group’s N Scale layout, ‘Solent Summit’.

‘Solent Summit’, which has appeared on my website many times over the years, is a modular layout built by members of the Gosport American Model Railroad Group.  Back in 2015 I built the Warsash ‘Y’ module which incorporated a large scratch-built timber trestle.

Here’s the ‘Portland Rose’ running over the trestle at the Andover show in 2016.

Not wanting to do anything less spectacular I set my sights on the famous US railroad landmark, the Tehachapi Loop.

The Tehachapi Loop is in Kern County, Southern California.  It’s on Mojave Subdivision, the line which connects Bakersfield to Mojave, and runs through the Tehachapi Pass over the Tehachapi Mountains.  The line is currently owned by the Union Pacific Railroad but was constructed by the Southern Pacific between 1874 and 1876.

The route up the Tehachapi’s was challenging and the railroad wanted to limit the gradient as best they could.  At one location, between Woodford and Marcel, which was christened ‘Waylong’ after W.A. Long, who was the Southern Pacific District Roadmaster, the route simply became too steep.

To overcome this a loop or helix was constructed at a steady gradient of 2.2%, which lifted the line by 77′ before it carried on up to the pass. The actual loop is 0.7 miles long, In the screen shot below from Google Maps you can clearly see the loop.

There are other loops like this in the US; on the former Western Pacific route through the Feather River Canyon is the Williams Loop, but what makes the Tehachapi Loop interesting for me is that it’s also a passing point.  Just after the line passes under itself, climbing up the hill it splits in two, and then rejoins itself further up the line creating a passing place.  Shorter trains can be waiting in the loop, crossing above the line below, while upcoming trains pass under the waiting train and, if they’re long trains, actually cross over themselves while passing the first.

The Tehachapi Loop has been modelled many times and at the Golden State Model Railroad Museum there’s a great example of it in N Scale.

However the GSMRM is a fixed layout with space, Solent Summit is not.  But I like a challenge and plans were drawn up, with a bit of modeller’s license, to create a 5′ by 4′ module which would incorporate the loop at a sensible radius and give a decent height increase without making it too steep.

The idea is to create a corner module with the train entering from the left and exiting from the top.  This should give optimum viewing for the loop.  The result, as shown below, gives a rise of 2.5″ at a gradient 2.2%, on the inside track, which has a radius of 20″.  The outer track, which has a bigger radius, has a gradient of 2.1%.  This plan also creates a passing point which can hold a 13.5′ long train.

Although the gradient matches the real loop, the elevation gain is only equivalent to 33′ as opposed to the 77′.  But what goes up must come down and for us 2.5″ is enough.  The other issue is the radius.  At 20″ it looks sensible but when you factor in the weight of a 25′ train navigating a 450° curve the risk of it pulling in on itself is high.  But the only way to find out is to try it.

The baseboard, being bigger than our normal 12″ wide construction, needed a little thought as it has to be easy to move, but strong as well to protect the layout in transit.  All of our modules are in pairs so when put together they form a solid box with the layout inside.  The Tehachapi Loop module would be the same consisting of two 2′ by 5′ modules. The back scene on the short side would need to be removed for transport.

The back scene also forms the sides to the box, so the front section needs the extra pieces shown in red to be bolted on to form the box.

The lowest level, where the line enters the module would be flat solid timber. The track bed carrying the tracks up will be laser cut and supported on timber posts. This track bed is made from 6 sections, as shown below, allowing it to be cut from one piece of wood.

The actual laser cutting was done by Model Railway Solutions.

With baseboards constructed and the track bed cut out it was time to start thinking about setting out the parts.  Below you can get a rough idea of the size with a UK Mk1 coach sat on the loop.

Next week I’ll show you what the loop looks like with all the track work complete and I’ll have some pictures from the first test run to share with you as well.  The 3D printed gears should have been delivered by then so I’ll get back to them the week after.

Bachmann HO US 4-8-4 Replacement Axle Shafts & Gear – Update

This week I have an update for the HO US 4-8-4 Replacement Axle Shafts & Gear set.

It appears I made a mistake with the hole diameter in the main drive gear, my apologies to anybody who has purchased one. The hole was larger than the hole in the axles meaning the rear wheels would not stay in the gear.

The good news is this has now been rectified and the current model on Shapeways is correct.  The parts are also available separately and they can all be found in my Shapeways Shop or via the links below.

Axles & Gears

Axles Only

Gear Only

However that doesn’t help anybody who has already purchased the gear set with an oversized hole. For those who did I will replace the drive gear for free. Please get in touch through the contacts page or email me directly at jamestrainparts@yahoo.co.uk and include the date which you purchased the kit.

Replacement gears seem to be in great demand at the moment and next week I should have some more to share with you for some UK OO locomotives.

N Trak Date Correction

To start with this week, I need to make a correction to last week’s post.

The N Trak convention in Bournemouth was not last weekend, it’s this coming weekend; 8th to 10th March 2019.  However it is still at the Trouville Hotel.  My apologies to anyone who went down last weekend.  You can read a bit more about the 2017 convention here and the 2014 convention here.  I’ll be there over the weekend if you’re in the area and want to come by and say hello.

As for a post this week I’m going to have to skip to next week as I’m rather behind and I need to concentrate on the projects on the bench.  But I’ll be back next week with some highlights from the N Trak convention.