My Scratchbuilt Covered (and lift) Bridge

[Steve]

Lovely stuff. Just out of curiousity, on the real thing what actually is the reason for making a covered bridge? Seems a lot of extra work. Is it for weather protection?

Thanks!..... when I was considering this bridge last year someone asked the same question so I looked it up on the mostly reliable Wikipedia site......

Regards
Rob

Would this be why old people wear hats , preservation

 

[robsmorgan]

I've only got one at the moment Steve, my intention is to build another loop this spring and I may need another lift bridge to get access to my shed..... but I was impressed by a swingbridge from another GSC post - might be worth covering!

Regards
Rob

 

[gregh]

I like your covered bridge and it's alway good to get feedback on
the results of using new materials. It's good news that the
corrugated plastic board lasts outside, even in your winters. If
only we had that Evostick glue here in Aus. I'm always looking for the
'perfect' outdoor glue.

Your bridge hinge is a great idea. I've always put the hinge pivot
above rail level to allow it to clear and it then looks ugly. Your idea
is very neat. I'm not sure about using steel rulers though -
aren't they a bit too flexible? Would steel strips be better or do you need the flexibility?

BTW, your dimension of 9mm on the dwg is probably supposed to be 9 cm.

 

[gregh]

It was used as snow protection and also to give the bridge a little bit of extended life.

True. Lots of these old bridges were made using laminated timber arches - see this pic of one I saw in New Hampshire.

Laminated timber bridges had a major failing - the timber rotted between the laminations and couldn't be seen. Also it was impossible to replace any of the rotted timber because as soon as you remove some wood from the arch it collapses. (unlike truss bridges which can have temporary bits installed while you remove one for repair).
Hence you build a roof over it to keep it dry !

Timber arches fell out of use but here is a reasonably modern one in South Dakota made from treated timber.
http://www.flickr.com/photos/80651083@N00/141702441/

 

[robsmorgan]

Thought the covered bridges were road traffic only not rail?

Guess who hasn't watched Buster Keaton in The General!
(and Disney's The Great Locomotive Chase for that matter)

Off to Love Films Ross!

Ha Ha!

Rob

p.s. Gregh is dead right I should have indicated 9cm not 9mm in the 1st diagram - haven't started my Z gauge version yet!