Discover more from Thinking Through
On Rails in Mt. View California 🚂
(3 Min Read) Data on rails
This post is not about Ruby on Rails. It's about the rail on which trains run, specifically CalTrain in Bay Area. I wrote this post because I was curious about the public data that Rails shares.
During a recent commute, I was waiting at an Mt. View Caltrain station, and my gaze went to the train tracks. The two parallel rails have a number on them.
1360 RE VT RMSM 1999
What does it mean? It was the code to identify rails as they are laid across the tracks. But what did each of the numbers/words mean? So I started looking at what each of them was. Here is the breakdown (tl;dr at the bottom)
1360: It's read as 136, and 0. 136 represents pounds per yard rail (3 feet). This may be the most common weight for rails. The 0 represents the month of production (not confirmed). Here are some fun facts about this number:
There were no uniform rails sizes before 1893. Every company made its own. You can see the problem here.
The lightest rail was 60 lbs per yard that were installed till 1995.
The heaviest rail laid in the USA is 155 lbs.
The heaviest rails proposed are 170+ lbs. But it required special treatment for wear and tear, so it has yet to become famous.
Why is weight significant: The heavier the weight, the faster a train can travel. Now I want to know the rail weight of Japanese Bullet Trains.
RE is the rail section. It's a way to identify the engineering association that established the design specifications for the rail. The RE is the American Railway Engineering and Maintenance-of-Way Association (AREMA) abbreviation.
VT: Indicates hydrogen elimination method, i.e., vacuum treated, meaning the molten steel is exposed to vacuum during cooling to remove dissolved Oxygen which can cause pores and inclusions to form in the steel.
RMSM stands for Rocky Mountain Steel Mills, a division of Oregon Steel.
1999 is the year of production.
So now the question was, what about height, width, and length? If the weight changes, then one of the dimensions has to change to pack the extra weight.
We know length can change because the weight is per yard or 3 feet of length. So it's either height or width.
Changing height seems risky, but there may be some margin of error. After all, the rails are laid on concrete blocks that are on rock beds on top of hard soil. With the locomotive's weight running on it, the track/floor is bound to compress. So that may change track alignment. Adding height as a variable is a nightmare for track installers. A possible explanation is that train wheels are much better are stepping up/down on rails with different heights.
So is its width? Maybe. But there are two types of widths, i.e., bottom width and top width. Visually bottom is more than the top, and it makes sense. This prevents rail rolling over as a broader base provides more support. (Fun fact: There were square rails where the height and width were the same).
Anyway, back to the topic of width and height. I found the following
115RE is 5.5" wide and 6.625" high.
131RE, 132RE is 5.5" wide and 7.125" high.
133RE is 5.5" wide and 7.063" high.
136RE is 5.5" wide and 7.313" high.
140 RE are 6" wide and 7.313" high.
152 PS and 155 PS are 8.00" high.
The rails that are laid in BayArea near Mt. View station are:
136 lbs per yard
Manufactured in Jan or 0 months.
It follows American Railway Engineering and Maintenance-of-Way Association (AREMA) design specifications.
Is vacuum treated
Manufactured by Rocky Mountain Steel Mills, a division of Oregon Steel.
Manufactured in the year 1999.
Each rail's width and height are 5.5" wide and 7.313" high.
While that was a curious data-hunting detour, it was a fun one. I am now more curious about
How wide should rails be from each other
What's the weight ratio of concrete blocks and how much space is between them, and why
How many concrete blocks have to crack in a section before they have to be replaced,
What's the error margin on rails alignment,
Are there specific wheels for specific rails,
What's the maximum speed (on paper) for each rail and specifically for the CalTrain tracks,
What kind and direction of force do rails experience (down & outwards, maybe)
Should station rails be replaced sooner than tracks on mid-stations, considering train stands on stations apply more pressure?
Do bullet trains have special rails?
How do you inspect if the rail is still good after a crash?
How does a train get derailed?
All these questions are for my next train ride. The Caltrain has reached San Francisco station, and it's a good time to end this post that I wrote while riding the rails that got me here.