Characteristics and Misconceptions of Dynamic Train Sets

Purely in terms of principle, the dynamic train sets do not have advantages over traditional trains, but rather increase the trouble of organization and maintenance. But in practice, specific models and specific applications of the right combination of environment can make the train sets have traditional trains do not have a huge advantage - of course, there are also configurations and the reality of the disconnect between the mistakes. Specifically in China, the rolling stock generally has the advantages of strong acceleration ability, strong climbing ability, easy to change direction and so on.

Strong acceleration ability

This advantage comes from the large dynamic drag ratio. Do the same weight conversion, in the case of sufficient power and power output control is reasonable, the greater the dynamic drag ratio, the greater the train can play the traction force.

In China, the conventional traditional passenger train is generally a locomotive traction large group of coaches, locomotives 88 tons or 132 tons, 880 tons ~ 1100 tons of coach group, power concentration, dynamic drag ratio is very small, resulting in the train can play a very small traction; and the dynamic group of mostly decentralized power, even if there is an occasional centralized model of the power, and the dynamic drag ratio is still greater than the traditional large group of passenger trains. This leads to two characteristics at the same time: the dynamic train set acceleration ability is stronger.

The advantage of stronger acceleration is that the train can return to normal operating speed in a short time after leaving a station or passing through a slow speed zone, which brings a series of benefits.

For passengers, this means that a train with the same maximum speed can stop at more stations in the same length of time, making it easier to get around, or in the case of mixed routes, travel time is shorter than that of a conventional large-format coach.

For dispatchers, this means less additional time for trains to start and accelerate, making them easier to dispatch and more likely to improve the efficiency of railroad operations.

For manufacturers, it means that they don't have to scramble to increase the maximum permissible train speed in order to guarantee the average speed - saving both the cost of building cars and the cost of repairing roads.

Myth: "This advantage is absolute and indiscriminate."

Conventional trains with small formations, conventional trains with double locomotive haulage, and certain conventional trains with double locomotive haulage can likewise enter the field of weakly-powered dispersal, with a high level of flat-out acceleration. This is more common overseas, just less common domestically and not universally relevant. I've also seen reports that a commuter line used to use a DF11G to haul three 22 coaches one day, which falls into the strong power dispersion category, but this occurs much more rarely. So domestically, this advantage has become almost exclusive to moving trains.

Strong hill-climbing ability

This feature has been incidentally mentioned in the previous feature, and also comes from the large dynamic drag ratio. Strong power dispersed train in the case of sufficient power in the 2% continuous grades can still maintain the ability to quasi-speed or even high-speed operation, while the weak power dispersed system can only be a small step up, the power concentration system is even difficult to even start, start can only be slowly dawdling forward.

China's shortlisted high-speed trains are all strong power dispersal trainsets, strong climbing ability and ramp speed ability for high-speed rail lines to provide great convenience, can effectively reduce the line construction and maintenance costs. China's traditional trains and self-developed rolling stock are due to the dynamic drag ratio or insufficient power and do not have in the continuous large gradient line at high speed or quasi-speed through the ability, so this piece of the market by only technology and joint venture technology to fill.

Myth: "This advantage is not absolute and indiscriminate."

Single locomotives with a dynamic towing ratio is generally 1:0, the power is super-dispersed, the strongest climbing ability. Multiple locomotives towing a small number of locomotives also have great hill climbing ability. And in Japan a and the gradient is too big on the line, even if the locomotive group, also need to add a complementary machine. Just such a situation is not representative.

Convenience

Chinese traditional trains, the operation of the change of direction step is "into the station to stop - remove the front end of the locomotive - the end of the train to re-hook the locomotive - and again out". And the train sets, as long as still remain in the normal operating state of the group, the two ends of the train will inevitably by the driver's office, each driver's office can be manipulated throughout the train on the power and braking equipment, the change of direction only requires the driver to go to the other end of the train's driver's office. This eliminates the step of locomotive shunting operations, thus saving the time of direction change, and also reduces the time of the station line occupied by locomotive shunting, and also reduces the chance of personal injury due to the removal of the car, trailer accidents.

Myth: "This advantage is absolute and indiscriminate."

Conventional trains can do this too. The train is hooked up to a locomotive at both ends, or a locomotive at one end and a control car with a driver's cab at the other, and then a reconnecting cable is run through the entire train so that the driver's cab at both ends can control the operation of the entire train in terms of braking capacity, which allows the change of direction to be done without removing the hangers. However, this mode of operation does not exist in the country, so the operation of the direction of change does not take off the hook in the country is only the patent of the rolling stock.

Luxury, comfort, high speed

This is the biggest misconception.

The most common use of trains is for inner-city and suburban commuting, and the core value of these trains is to carry large numbers of passengers at acceptable speeds and in comfort. Luxury and comfort come from the high consumption class trains, and the train sets are not necessarily related. Some of the domestic media vigorously publicized the rolling stock, especially the CRH series, belonging to the high consumption grade high-speed trains, which allows the public to produce a "rolling stock luxury, comfort, high speed" of the misperception.