KNOW WHY STONES ARE NOT LAID ON METRO TRACK UNLIKE OTHER TRACKS !!

 

You might have observed that stones are laid beside railway tracks but when it comes to metro tracks,there are no stones laid near the track.We will discuss the reason for this in this article.

Let us first discuss why stones are placed near the railway track.The crushed stones you see alongside railroad tracks are what is known as ballast. Track ballast is packed between the sleepers, in the areas below, and on the sides of railway tracks. A railway sleeper is a rectangular support that is usually kept perpendicular to the tracks. The ballast distributes the load of the sleepers (which in turn bear the load of the train on the track, held by clips) across the foundation, allows for ground movement, thermal expansion and weight variance, allows rain and snow to drain through the track, and prevent the growth of vegetation that would quickly take over the track.

 

Read:KNOW WHY POINTED STONES ARE PLACED ON RAILWAY TRACKS !!

When it comes to metro track,it uses ballastless track.Ballastless tracks have different designs to absorb the vibration.They have high initial costs but less maintenance costs. That is why their whole life cost is lower than ballasted tracks. 

 
Since the metro tracks are elevated, drainage and growth of vegetation aren't much of an issue, and the solid structure are designed to bear the wheel loads, and transmit them safely to the earth, there is no requirement of using ballast underneath the track.

There are safety & maintenance issues as well for using ballasts on the elevated sections, as they do pose the risk of flying off and hitting people using the space in the vicinity of the viaducts.
Another reason is that speed is very limited in metro as stations are very close ,that is why impact load is less (for which ballast is used).

Why Railways use ballasted track?

1.Ballasted track is good in the normal speed railway and fast speed railway.

2.Ballasted track requires low investment cost.

3. Ballasted track is usually easy to lay.

4.Ballasted track has good drainage performance.

5.Non-ballasted track cannot be laid in some area like clay deep cutting.

Nevertheless, whenever Rapid transit systems run on the ground, they use traditional methods of load distribution involving sleepers and track ballasts because they are much economic as compared to constructing reinforced concrete girders at places where the latter are not required. Such examples can also be found in Delhi Metro. At sections near Yamuna bank station on blue line, Delhi Metro runs on the ground and uses traditional track ballast.

KNOW WHY POINTED STONES ARE PLACED ON RAILWAY TRACKS !!

Traveling by train is an amazing experience in itself. You get an amazing view of nature. One more thing that you almost always see throughout your train-journey are those small stones lying alongside the track on which your train races?

Have you ever given any thought as to why there are almost always stones alongside a railway track? We will discuss the reason behind this in this article.

The crushed stones you see alongside railroad tracks are what is known as ballast. Track ballast is packed between the sleepers, in the areas below, and on the sides of railway tracks. A railway sleeper is a rectangular support that is usually kept perpendicular to the tracks. These are usually made of wood or pre-stressed concrete, although the latter is more widely used today. The function of railway sleepers is to hold the rails upright and properly spaced. In short, their purpose is to hold the sleeper ties in place, which in turn hold the rails in place.

The rail track is subjected to heat expansion and contraction, ground movement and vibration, precipitation build-up from rough weather, and plant growth from underneath. The ballast distributes the load of the sleepers (which in turn bear the load of the train on the track, held by clips) across the foundation, allows for ground movement, thermal expansion and weight variance, allows rain and snow to drain through the track, and prevent the growth of vegetation that would quickly take over the track.

WHY CRUSHED POINTED STONES ARE USED??

If you put smooth, round pebbles in the ballast, then they might roll or slide over each other when a train passes over the tracks; therefore, they would fail at their main job – providing solidarity to the tracks. Given that fact, you need stones of a specific type that won’t move around too much, except by kids chucking stones near the tracks, of course!

In order to guarantee that the stones stay in place, they use sharp and edged stones in the ballast.

KNOW WHY THERE IS NO REVERSE GEAR IN MOTORBIKES !!

You might have observed that motorbikes do not get reverse gear. Let us discuss the reason behind this in this article.

The front fork of all bikes has an angle and "rake", which assist in keeping it going straight and make it easy to correct balance without falling over. This does not work in reverse very well, as the rear wheel is fixed. You can train yourself to ride backwards, but it is very difficult. In addition, it would be dangerous on a motorcycle and pointless since motorcycles have a tight turning radius and you can simply push it backwards with your feet. They are not used because you can easily push your bike backwards with your feet.

Reverse gear takes up space and adds weight. Space is limited in motorcycle. The bikes transmission is not designed in similar fashion as that of car due to the space restriction.

 

Some heavy touring bikes like Honda GL1800 Goldwing and BMW K1600, which weigh over 375kg each and are difficult to push do have a reverse gear, to assist in getting out of parking spaces only. It uses the starter motor, not the engine, to give it a slow push.