Ballast on Bridges?

[simon1966]

I am about to ballast my track and realized I do not know if the ballast should be put on bridges. I have a truss bridge and a plate girder bridge.

Thanks

[cwclark]

I have seen some plate girder bridges with ballast on real railroads..but none on truss bridges...I also like to paint the bridges light grey and weather them with floquil rust and rail brown instead of the solid black color that comes on Atlas bridges...most of the real SP bridges in this neck of the woods were always painted silver, but for modeling, I find that silver paint sticks out like a sore thumb..the light grey is a bit more subtle... my favorite bridges to model are scratch built..Some dow rod, balsa wood, glue. and straight pins make a fantastic looking trestle bridge..and they don't need ballast...Chuck

[Fergmiester]

I have only seen ballast on plate girder bridges and this is something I put a bit of research on as I had similiar questions a year ago

[orsonroy]

Ballast on bridges is sorta rare, and the bridges are specifically called ballast deck. Micro Engineering is the only company that specifically makes an HO ballast deck bridge.

[simon1966]

Thanks for the responses guys. This close to real time feedback is a real benefit. Not that my wife approves! My home office is 8 ft from my train room, so it is very easy to get distracted from the day to day grind [:D]

[AntonioFP45]

Hey Amigos,

As long as we're on the subject, I've seen photos of ballast on plate girder type bridges. What useful purpose does the ballast serve?

Ballast allows for good drainage on tracks mounted on roadbed but It would seem that on bridges, rain could easily fall through the girder openings on the plate bridges.

I'm planning a "deck" type of bridge that would pass over a public street on my future layout. Would like to make it look authentic.

Thank you.

[Anonymous]

Hello all!

Ballast on bridges. Yes plate girder bridges have ballast and i've even seen a pony truss bridge with added screens to keep the ballast from falling through and hitting some un expecting boaters below.....railroads have a funny way of improvising thats for sure!

[DSchmitt]

From Bridge and Trestle Handbook by Paul Mallery published by Carstens (Railroad Model Craftsman publisher)

"For high speed running on the prototype stamndard ballasted track construction is continued over bridges. Thus modern main lines, even some built before 1900, tend to use ballasted rather than open floors. A ballasted floor is simply a trough to contain the ballast and ties of normal trackwork and its supporting members. The trough may be an integral part of a concrete beam or slab bridge, a separate trough resting on any form of bridge, or one utilizing otherwise existing bridge members...........Ballasted floors are always easier to model than open floors as they permit normal track construction and completely conceal the structure under the track......."



Any kind fixed span bridge could be ballasted.

[mls1621]

Simon,

Micro Engineering makes bridge and trestle track with the correct tie spacing, it looks really good on a truss bridge.

I've modified three Kato N scale truss bridges with it and built a scale 200 ft trestle for my neighbor's layout. It really adds realism to the scene when little details like the tie spacing is correct.

Just my opinion, I could be wrong.

[M636C]

The problem with prototype bridges with a ballasted deck was that the ballast collects dirt and dust, and water when it rains, and this causes the deck to rust (if steel) or rot (if wooden planks). Most woooden trestle bridges had rails directly attached to ties for this reason.

The advantage of a ballasted deck is that it allows the position of the rails to be adjusted in the ballast (called tamping, lifting and lining) the same as in ordinary track.

If the bridge is rigid, the track each end has to be lined up to it carefully, to avoid or reduce any bump or jerk as the train passes on to or off the bridge. With a ballasted deck, the bridge an be treated as any other piece of track, and the tamping machines can run right across the bridge, adjusting the track into line, both vertically and horizontally.

Most modern bridges have reinforced concrete troughs carrying ballasted track. Since, in a model you don't have to adjust the track in the ballast to keep it in line, it's your choice!

Peter

[Anonymous]

Hi Peter,

your right but ballasted tracks at concrete bridges are older - I mean more than 70 years old. 30 km in the north is the at building time - about 1920 I think, possible earlier - biggest concrete bridge in Germany. With a ballasted track!

The brandnew 150 feet high Lahn Riverbridge of the new highspeed line was built in the next generation - like the whole line. The concrete ties are fixed in a bed of concrete without ballast! Very expensive building but cheap maintenance - WE WILL SEE !!!!!!!!

[AntonioFP45]

M636C

Once again, thanks!

I now have a much better understanding, as originally to me it didn't seem to make sense. I've decided though that on my layout I won't ballast the bridge.

I remember growing up in the New York area that various deck bridges were of both types: ballasted and non-ballasted. I used to enjoy walking under an unballasted bridge as a train "slammed by" overhead.

Cheers!

[Werl]

Hi Simon, I have a question about the Kato N single track truss bridge. Will the Kato bridge track mate with Atlas code 80 or will it  have to be removed. Also there appear to be substantial supports on the ends of the bridge. Can these be removed so standard US style supports be used? Thanks in advance.

[tstage]

Simon hasn't been a regular around here in quite a few years so the prospect of him responding to this 19+year old thread is pretty remote.  Maybe someone else can chime in and answer your question.

Tom

[BigDaddy]

Werl start a new thread, it's FREE.   Your question isn't relative to the subject of this thread. 

Asking a specific question in the title of your new thread: "Does Kato bridge track mate with Atlas code 80?" will get you the eyeballs of people who actually know.

[Werl]

Thanks BigDaddy. I may start a new thread to help others, but I went ahead and bought the Kat o bridge and found that the foward thinking engineers at Kato recognized the potential of the structure for othe brands. The abutments now snap off and on without any glue and the bridge track will definitely matr with Atlas track. However the track does not look at all like US bridge tracks! No matter, the Kato engineers have made track removal easier- the track is no longer glued to the bridge- it is held by one Phillips screw in the middle and four plastic clamps on the end. To replace the track with something similar to US standard, remove th screw and cut the tops of the end clamps with a chisel blade and the stock track drops right out. In my case I replaced the track with a peice of Micro Engineering bridge track. The conversion of this structure is easy as ever thanks to Kato's vision.

[Geared Steam]

M636C

The problem with prototype bridges with a ballasted deck was that the ballast collects dirt and dust, and water when it rains, and this causes the deck to rust (if steel) or rot (if wooden planks). Most woooden trestle bridges had rails directly attached to ties for this reason.

Peter

 

 

I'm not so sure about that, Milwaukee Road was famous for having ballast on their bridges, most are still standing as built back in 1914. They used the concrete trough method, seems to have worked fine w/o rusting the bridge away, and it was abandoned in 1980, so its had 40 years of zero maintenance, and this was a branch line.

 

 

 

 

 

[BEAUSABRE]

DSchmidt I knew Paul when I was a teen aged member of the club he belonged to. He talked me into my first scratch building project, a lattice truss for one our branch lines (Lattice trusses stopped being built prior to 1900, our story was that it was a mainline bridge that had been replaced by a modern one and re-erected on the branch to replace a wooden Howe truss. Such frugality was not uncommon) and gave me a copy of his book to guide me, telling me to keep it when the project was completed. It is still available Bridge and Trestle Handbook: Mallery, Paul: 9780911868791: Amazon.com: Books

He came by his knowledge of bridges naturally - his father was Chief Bridge Engineer on the New Haven.

From talking to Paul. I learned that the ballasted deck bridge was adopted for use on high speed and/or heavy traffic lines and the ballast cushioned the ride. 

[Track fiddler]

We need no ballast here.

 

Tf