Bridge too narrow

Help with designing your track work
User avatar
Walkingthedog
Posts: 1908
Joined: Thu Oct 04, 2018 5:51 pm
Location: HAZLEMERE, BUCKS.
Contact:

Re: Bridge too narrow

#11

Post by Walkingthedog » Sun Jan 12, 2020 9:54 am

About 50mm on a straight.
Nurse, the screens!

User avatar
Brian
Site Admin
Posts: 1012
Joined: Thu Oct 04, 2018 3:49 pm
Location: SE Kent
Contact:

Re: Bridge too narrow

#12

Post by Brian » Sun Jan 12, 2020 11:09 am

Peco use two OO track spacing. Setrack which is absolutely the same as Hornby and is at 67mm centres. Streamline which is set to 50mm centres. As a 'rule of thumb' where twin tracks are parallel add 28mm to their centre spacing to gain the overall width e.g. Setrack/Hornby = 95mm and Streamline = 78mm sleeper edge to sleeper edge +/-1mm.
Track centres are gained from placing two of the same handed points together to form a cross-over and the measurement is the two straight tracks running in parallel.
This is the Hornby track geometry, but Peco Setrack is exactly the same spacings. https://www.hornby.com/_assets/files/Tr ... ry-PDF.pdf

The Metcalfe bridge and viaduct all accept Setrack (67mm centre) spacing. The PO240/241 Viaduct is stated to be 100mm inside (ample for Hornby or Peco Setrack) and the bridge PO246/247 is stated as being 128mm overall wide which should give at least or very near the same as the viaduct in track room width. in fact you say you're bridge has 105mm inside the walls.

Your rule shown in picture 2 shows the correct width of 128mm and that gives roughly 100mm inside for the bridge deck. If you want the bridges tracks to look more prototypical then bring the parallel tracks in more from their vastly over scale 67mm they are conventionally set at. :o
Image << Click the Icon to go to my website

User avatar
Walkingthedog
Posts: 1908
Joined: Thu Oct 04, 2018 5:51 pm
Location: HAZLEMERE, BUCKS.
Contact:

Re: Bridge too narrow

#13

Post by Walkingthedog » Sun Jan 12, 2020 11:23 am

If you look at Nicks picture there obviously isn’t room for 67mm track spacing. The track is hard against the walls. Very odd.
Nurse, the screens!

User avatar
Brian
Site Admin
Posts: 1012
Joined: Thu Oct 04, 2018 3:49 pm
Location: SE Kent
Contact:

Re: Bridge too narrow

#14

Post by Brian » Sun Jan 12, 2020 11:28 am

The picture shows the right hand sleeper ends slightly further away from the inside face of the wall than the left hand side. Re positioning the tracks to the right slightly or the bridge to the left will equal outside distance. Are the two bridge tracks running dead parallel?
But for better realism bring the two tracks a little bit closer together, but this isn't going to be easy with Setrack, especially as there is a level crossing just before the bridge!
Image << Click the Icon to go to my website

User avatar
Walkingthedog
Posts: 1908
Joined: Thu Oct 04, 2018 5:51 pm
Location: HAZLEMERE, BUCKS.
Contact:

Re: Bridge too narrow

#15

Post by Walkingthedog » Sun Jan 12, 2020 11:36 am

Yes you are right. Still a bit tight though. Definitely flexi is the way to go.
Nurse, the screens!

User avatar
Brian
Site Admin
Posts: 1012
Joined: Thu Oct 04, 2018 3:49 pm
Location: SE Kent
Contact:

Re: Bridge too narrow

#16

Post by Brian » Sun Jan 12, 2020 12:17 pm

Walkingthedog wrote:
Sun Jan 12, 2020 11:36 am
Yes you are right. Still a bit tight though. Definitely flexi is the way to go.
Agree WTD. I would replace the left hand track with flexible track and bring it over slightly towards the fixed Setrack line by 10mm or so and re position the bridge to the right a little if possible.
Alternatively replace both lines with flexible track spaced closer together and then somehow arrange for them to match in with the curved track immediately after the bridge.
Image << Click the Icon to go to my website

Nick8873
Posts: 9
Joined: Sun Dec 01, 2019 7:33 pm
Contact:

Re: Bridge too narrow

#17

Post by Nick8873 » Sun Jan 12, 2020 1:52 pm

thanks for the comments guys what's the best way to cut the flexi track to length and do we ballest on a bridge aswel?

User avatar
Brian
Site Admin
Posts: 1012
Joined: Thu Oct 04, 2018 3:49 pm
Location: SE Kent
Contact:

Re: Bridge too narrow

#18

Post by Brian » Sun Jan 12, 2020 2:08 pm

Nick8873 wrote:
Sun Jan 12, 2020 1:52 pm
thanks for the comments guys what's the best way to cut the flexi track to length and do we ballest on a bridge aswel?
Cut track ideally with a Xuron rail cutter but if careful you can use a Dremel with metal slitting disk or a Razor saw or even a fine toothed blade in a junior hacksaw. If using a Razor saw or hacksaw I would recommend making up a small wooden block a little wider than the rails and then cut two parallel slots into the block the same width apart as the two rails. Place the block over the rails to hold them securely in place and cut the rails.

On that type of bridge the track would be ballasted.

This is the basic idea for a cutting block to hold the rails firm when sawing them...

Image
Image << Click the Icon to go to my website

Nick8873
Posts: 9
Joined: Sun Dec 01, 2019 7:33 pm
Contact:

Re: Bridge too narrow

#19

Post by Nick8873 » Sun Jan 12, 2020 2:19 pm

ok thanks for the advice
Nick

User avatar
Brian
Site Admin
Posts: 1012
Joined: Thu Oct 04, 2018 3:49 pm
Location: SE Kent
Contact:

Re: Bridge too narrow

#20

Post by Brian » Sun Jan 12, 2020 2:25 pm

Cutting block idea shown above. Added later after closing post.
Image << Click the Icon to go to my website

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest