Hi George,
I looked into many aspects in designing culvers and water flow for 25 years storms (hydrology of the upstream section).
The goal for volume 1 was Civil Engineering for the non-engineer.
I show photos of drop inlets (manhole boxes) as well as good and bad culvert photos used on Live Steam Tracks (mainly Mid-South in Columbia TN and the old North GA Live Steamers track before the Southeastern Railroad Museum was moved).
I point out about when and when not to allow water controlled in pipes out. The best suggestion I came to was the use of short bridges or trestles over a watercourse. The short trestles make running the railroad more interesting.
1) for culverts, make sure you use properly built headwalls for both the inflow (upstream) and the outflow (downstream) ends of a pipe.
2) the largest erosion issue for a culvert is an improper or no headwall (or a headwall made from loos large rocks or broken up concrete. If the headwall water depth covers (IIRC) more than about 85% of the height of the pipe, you will get whirlpools very similar to what happens with a sink full of water has its plug removed. These whirlpools are extremely powerful and might eate out the entire roadbed.
3) a short trestle will eliminate the need unless there is loose debris that makes the trestle opening too small to to function properly.
The rule of thumb for water control is get it into a pipe so it is fully controlled and do not let it out of the pipe until any outflow will not reach back and threaten the roadbed.
I saw an application where the original mainline used a 4-5" scrap of pipe and its length was about 12" with no headwalls. A new mainline was places uphill from the original. They used a 18" scrap pipe. under the new line. The first cloudburst sent a wall of water out of the 18" pipe into a ditch that was slightly deeper than the balast. The 5" pipe with no headwall could not handle the outflow from the 18" pipe and so about 4-5 feet of roadbed was washed out of the older mainline.
If the 18" pipe had been another 4-5 feet longer, it could have been tunneled under the original mainline and let loose some 2-3 feet beyond the lower track. This was a case of insufficient understanding of water and drainage. Both pipes were used PVC.
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www.ebay.com] for volume 1.
If you purchase my book(s). I will be glad to help out anyone who needs help. A book purchase is mandatory - I can then work through email or maybe telephone (I sometimes let my cell phone lapse for a internet dial-up).
Once I understand you question, I can tell you what page(s) to go to in the book(s) that cover the question. Then we can both see the same page in the book and work from there.
Since Civil Engineering Volume 2 is intended to help out those who want to check out their bridge design and/or overhead crane design (anything structural) I am willing to take on more of the design burden. The data needed to analyse the bridge or structure gets huge very quickly. I can help out with that. Depending on the bridge size and style, I might have to charge a token about for help.
The bridges and tunnels in Volume 3 are pre-analysed. I can show you how to figure out the "maximum" load allowed on the bridge
I have two other items that I will put into another volume of the book series - Surveying basics (covered in Volume 1) and how GPS errors can be eliminated. The signals chapter I have is not really Civil Engineering, but there are many misconceptions about signaling including that track detection causes cornfield meets. This is an improper understanding of signals. I have been asked a few questions and decided covering signals would help make the series a one-stop reference.
I've been asked to cover trackwork (mainly switches and crossings) and if I can do it, they might become future chapters.
Once again, I enjoy sharing knowledge and if I did not need the cash to live on, I would share it free. Sorry about the lengthy post.
Doug vV
