MISC | Newbie Question Thread

Ro-E said:

i love trains.
unfortunately, i live in a country where the train system...is no good.
it brings many questions to mind...

1.what is the difference between light and heavy rail?
2.what speeds do these usually achieve?
3.how fast do they accelarate?
4.how much heavier are heavy rail trains?
5. does this make them more dangerous?
6.does all the wheel sets onboard have brakes?
7. if all of the wheel sets onboard have brakes, how come length is limited?
8. can light rail serve intercity 200 km long lines?


hope you still have the energy to write...:nuts:
have a good day!

Click to expand...

As for questions 4 and 7, the maximum weight of 'heavy rail' trains is mainly limited by the strength of their coupling systems and the rails on which they ride. European 'buffer and chain' coupled freight trains are limited to about 750m in length and about 3000t in weight, this due to that relatively weak coupling standard. OTOH, trains on Russian 'broad' gauge lines and those on standard-gauge lines using AAR 'Type E' couplers (mainly used in North America, China and Australia, plus a few other places) can be far longer and heavier - this due to their much stronger couplers. The coupling standard used on Russian broad-gauge lines is about six times stronger than 'buffer and chain' and AAR 'Type E' couplers have about eight times the strength of 'buffer and chain'. 14.000t trains hauled solely by locomotives at the front are everyday things here in North America (IIRC, the theoretical maximum weight for trains with 'Type E' couplers is in the 25.000-30.000t range). With locomotives added elsewhere in the train, its length and weight can be greatly increased from those other limits.

Train lengths are also limited by lengths of passing sidings and yard tracks and weights can also be limited by the maximum ratings of electrical power supply systems on electrified lines.

The normal maximum freight car axle loading here in North America is about 30t.

I hope that this helps.

Yes, it is a little bit heavier than what runs in Israel.

Mike

1.what is the difference between light and heavy rail?
Basically heavy rail are normal standard trains, just like the trains in Israel. Light rail trains are as the name already suggests lighter then the average trains. In Europe there are several types of light rail, making it hard to explain what light rail actually is.

some examples:
* Trams running on train tracks, in some German cities the tram services in the cities were extended using existing train tracks into the region. Sometimes even mixed with heavy rail, sometimes over abandoned tracks.
* Metro like trains used for urban and suburban services. Using lighter trains to make a metro like system with a high frequency on existing train tracks. Lighter trains usually have a faster acceleration making them perfect for urban rail with small distances between the stations.
* Light Diesel Trains to serve smaller lines. The trains are cheaper to buy and maintain then the heavy trains. Lighter tracks can also be used, so therefor they also safe money on the infrastructure. These are usually used on smaller rural lines that have been neglected before because of the high cost of maintenance and low passenger numbers.

2.what speeds do these usually achieve?
Heavy rail: let's say 80 km/h to 350 km/h, it just depends on what the trains are used for.
Light rail: 80 - 120 km/h is the usual range, sometimes it's extended to 140 km/h but not really more. For faster trains you need a bit of weight to make them comfortable and safe.

3.how fast do they accelarate?
Light rail usually accelerates faster, but I don't know exact figures.

4.how much heavier are heavy rail trains?
You can better ask, how lighter are light rail trains because heavy rail is the norm. And the difference can be quite big, like in 25% lighter. And with the trams it's even more of course.

5. does this make them more dangerous?
Weight has an influence on safety but it doesn't go one way. You can say that heavy trains are more safe or even more dangerous then light trains.
Heavy trains are safer in a collision, because they are more sturdy build and therefor give the passengers more protection then the light weight light trains. But on the other hand the extra weight can also make an accident more dangerous because there's just 'more' train that can harm people.

The combination of heavy trains and light trains is always a cause of concern when it comes to safety.

6.does all the wheel sets onboard have brakes?
Usually trains have breaks on every axle.

7. if all of the wheel sets onboard have brakes, how come length is limited?
some more reasons for maximum lengths of trains.
* Train Protection - if a block system is used with the signaling, trains often can not be longer then a block.
* maximum platform length - why allow trains that are longer then the longest platform on your network?

8. can light rail serve intercity 200 km long lines?
Light rail isn't suited for faster trains on longer distances. But if the tracks don't allow high speeds a light train can also be used on intercity services, it happens in some Eastern European countries.

first i'd like to thank you guys...you've been surprisingly helpful :banana:

Stainless said:

Trams can have quite suprising acceleration when you compare them to subway trains, even when comparing them with busses, it can knock you off your feet if you are not careful. .

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this is good! well...not if your elderly or careless...
if accelaration is uncomfortable it should be softened.
sudden bursts and brakes are some of the reasons why people dislike public transport.

Momo1435 said:

2.what speeds do these usually achieve?
Heavy rail: let's say 80 km/h to 350 km/h, it just depends on what the trains are used for.
Light rail: 80 - 120 km/h is the usual range, sometimes it's extended to 140 km/h but not really more. For faster trains you need a bit of weight to make them comfortable and safe.

5. does this make them more dangerous?
Weight has an influence on safety but it doesn't go one way. You can say that heavy trains are more safe or even more dangerous then light trains.
Heavy trains are safer in a collision, because they are more sturdy build and therefor give the passengers more protection then the light weight light trains. But on the other hand the extra weight can also make an accident more dangerous because there's just 'more' train that can harm people.

The combination of heavy trains and light trains is always a cause of concern when it comes to safety.

7. if all of the wheel sets onboard have brakes, how come length is limited?
some more reasons for maximum lengths of trains.

* maximum platform length - why allow trains that are longer then the longest platform on your network?

Click to expand...

2. this is very interesting...due to the short distances and technical issues israeli trains rarely pass 120 km\h. i find myself driving alongside them a lot.
maybe a fast light train would suffice.
5. i guess if you can knock out the obstacle in a collision its better to be in a heavy train... but 'more' train that can harm people just sounds... horrifying.
7.i often find the platforms are ridiculessly long from a pedestrian POV...and yet it won't cost a whole lot more to make them longer... this is a reason, but doesn't sound so ristrictive to me.

mgk920 said:

As for questions 4 and 7, the maximum weight of 'heavy rail' trains is mainly limited by the strength of their coupling systems and the rails on which they ride. European 'buffer and chain' coupled freight trains are limited to about 750m in length and about 3000t in weight, this due to that relatively weak coupling standard. OTOH, trains on Russian 'broad' gauge lines and those on standard-gauge lines using AAR 'Type E' couplers (mainly used in North America, China and Australia, plus a few other places) can be far longer and heavier - this due to their much stronger couplers. The coupling standard used on Russian broad-gauge lines is about six times stronger than 'buffer and chain' and AAR 'Type E' couplers have about eight times the strength of 'buffer and chain'. 14.000t trains hauled solely by locomotives at the front are everyday things here in North America (IIRC, the theoretical maximum weight for trains with 'Type E' couplers is in the 25.000-30.000t range). With locomotives added elsewhere in the train, its length and weight can be greatly increased from those other limits.

Train lengths are also limited by lengths of passing sidings and yard tracks and weights can also be limited by the maximum ratings of electrical power supply systems on electrified lines.

The normal maximum freight car axle loading here in North America is about 30t.

I hope that this helps.

Yes, it is a little bit heavier than what runs in Israel.

Mike

Click to expand...

thank you mike.

one last question...
i understand that light rail trains accelarate better and heavy trains carry more and reach faster speeds-
at what speed\length between stations, can heavy rail be more effective in carrying more people per hour?
i realize this is a very complex question... if you can refer me to a good book or data source or research it would be perfect.
is there a formula? :colgate:

thanks again

Ro-E said:

i love trains.
unfortunately, i live in a country where the train system...is no good.
it brings many questions to mind...

hope you still have the energy to write...:nuts:
have a good day!

Click to expand...

1.what is the difference between light and heavy rail?
- light rail is defined as a lightly build system and/or trainset
- heavy rain is defined as a solid/robust system and/or trainset
- both definitions are so wide scoping that a light rail trainset here can be a heavy rail somewhere else and vice-versa
- "tipically" the light rail definition is reserved for the tram-stile urban trains ... everything else is just considered heavy rail (without the actuall heavy rail name attached) :cheers:

2.what speeds do these usually achieve?
- those monstruously heavy freight trains can be as long as 2/3km and 10.000 tons (or even more but it depends on what force their coupling system can handle)
- LRT trainsets can achieve up to 140km/h but are (usually) geared to 70/90km/h
- conventional trains are usually built to 120/140/160 km/h ... more than that and we enter the realme of high speed trains (speeds from 180/200 to 300/350 km/h)


3.how fast do they accelarate?
- comuter and metro trains can have accdelerations os 2,5m/s^2 ... but usually they are limited to much more confortable 1,2m/s^2


4.how much heavier are heavy rail trains?
- you can get "heavy rail" trains as light as a pair of wheelsets connected by a simple wood board ... and they are heavy rail.
- basically we only consider "light rail" the urban tram's ... and these can me made compatible with heavy rail standards.


5. does this make them more dangerous?
- no


6.does all the wheel sets onboard have brakes?
- that depends on the caracteristics of the trains themselves :cheers:
- as technology evolves the unbraked wheels are becoming increasingly more rare .. .I would say extint already ... but in last years there were way too many unbraked wagons. hno:


7. if all of the wheel sets onboard have brakes, how come length is limited?
- lenght is limited by the infraestructure (small platforms , signaling blocks , etc) or by train performance , and it can also be limited by capacity demand .
- theres no need for a 10km long freight train ... it would take a day or more to load and would be a nobrainer to route along it's way ... and over 400m passenger trains require extra large stations.

8. can light rail serve intercity 200 km long lines?
- in a word ... YES ... as long as it can achieve "sufferable speeds" and has good enough seating it can :cheers:

Stainless said:

Trams can have quite suprising acceleration when you compare them to subway trains, even when comparing them with busses, it can knock you off your feet if you are not careful. I guess they can draw a lot of power from the overhead wires compared to their weight when you compare them to a heavy train or diesel electric.

Click to expand...

Subway , Metro , Underground and light rail can be equiped with the same traction motors and the same gear ratios ... hno:

Back to the questions:

These "light rail" DMU's and EMU's can go as high as 140km/h






The "light rail" concept and specially the bias agains it is completely old news ... the light rail trains of today can travell as well in mainlines as any other train ... and can have the same (or even more) capacity than the old-school subway/comuter/intercity trains.

Basically the tram concept is much more evolved and adaptable than the old wooden passenger cars. :cheers:

^^ The trains in post #11 are DMU.

wizardist said:

I have a question, too.

We can see a railroad with standard gauge on the last foto. And we also can see a railroad, which is in the middle of the first, and its gauge is less than standard... So, what is this middle railroad for?

Click to expand...

http://en.wikipedia.org/wiki/Dual_gauge

Some tracks have three rails, so they can be used by trains built for two different gauges. There are some tracks for three gauges, but they are uncommon.

Here, in Japan, the left rail is used by standard gauge trains, the centre rail by Cape gauge trains (1067 mm or 3'6''), the right rail is shared by both.

The switch on the left is used to separate the two gauges: one branch can be sued only by standard gauge trains, the other only by narrow gauge trains.