Transportation has been one of the most important necessities since the early ages. In the past, people used animals for transportation. However, later, animal based transportation was not enough to catch people development velocity. Therefore, technology has been used since 19th century with the industrial revolution in transportation especially in railway systems. Subway is one of the products of industrial revolution. In the basic definition, subway is an underground urban railroad, usually operated by electricity. Over the last century, there has been an increase in the subway usage to make people’s lives fast and punctual. In fact, travelling with subway system is the most useful transportation system because of its healthy, economical and technological benefits. The first important advantage of subway systems are that they are healthy. In the first place, subway systems make people’s psychology better. As an example, subway systems avoid noise pollution. Hardy (2008) states that noise makes people more angry and enhances the possibility of heart attack, causing the EU 3% of ischeamic heart diseases in Europe ( para. 4). This shows that one can say people will be badly impressed by noise of vehicles in the transportation system without subway. Moreover, thanks to subway system, one can reach anywhere in time. As Jordan explains, currently used traffic systems should be abondoned because of soaring fuel prices, loss of time on traffic and the adverse effects on the environment. For this reason, that the metro systems grow into all over the place, can be an ideal solution for traffic problems. Thus making the psychology of people is a good subway system will be effective the use of performances of transport. Besides the fact that subway systems contribute to better psychology, they also cause less environmental pollution. J. Wargo, L. Wargo and Alderman state that altough people have learned to accept the smell of exhaust from the engine as an element of daily life, most countries are experiencing an epidemic of diseases aggravated by air pollution ( 2006, para. 2). With the subway systems, it is possible to transform the world into a cleaner place and to prevent certain diseases. In addition, the subway is a great advantage to delay global warming. In 2004, total number of vehicles in the United States issued 314 MMTC (CEV) that causes global warming. (J. DeCicco & F. Fung, 2006, p. 21). This evidence clearly shows that transport systems contribute to global warming, no subways. Of course, the subway system is the best alternative transportation system for less environmental pollution. The second important advantage of railway systems are that save the transportation time and cost. Firstly, railway systems are indispensible transportation vehicles in our time. Railway systems reduce the transportation costs. Agostini and Palmucci ( n.d ) state that a built metro station has a direct impact on reducing transport costs ( p. 9). That proves railway systems reduce the transportation costs. Besides, railway systems reduce the travel times. Gibbons (2005) states that subway systems directly saves on travel times to any remote destination (p. 150). This means, for less travel times railway systems should be used for congested cities. Related to this situation most countries are preffering railway systems. Humanity are in space age, and it supports the using of technology in subway systems. Principally, security members take charge of protecting the subway against terrorist attacks. For instance, special teams interfere instantly someone or something that looks suspicious with submachine guns. Kelly (2008) reports that special teams keep handy submachine guns like the Heckler & Koch MP5 made in Germany (para. 14).It is a fact that special teams give confidence to passengers hugely and terrorist actions can not nostly be organized. Furthermore, well-trained dogs help special teams when they are in an incapable situation. As stated by Kelly, each dog walks around the subway stations’ trains and platform for bomb searching. (2008, para 4.). Special teams not only are entrusted, but also well-trained dogs are used for the security of subway. Thus,security members, equipped with the last technological equipment, provide passengers a comfortable trip because of protection against terrorist attacks. Apart from contribution of security members , subway systems also protect with computer based security systems. Camera systems are one of the most significant security elements. As Policastro and Gordon mention, against many possible terrorist attack scenarios Operations Control Center (OCC) is used for emergency management decision by decision makers, and closed-circuit TV (CCTV) will have benefits in order to decrease the lenght of lost time in the future about analysing ( n.d, para. 2). With the new camera systems, suspicious people can be analysied in a short time. Apart from camera systems, chemical detection systems are mostly used, too. As stated by Policastro and Gordon (n.d), chemical sensors detect if an attack is, and if there are C/B ( Chemical/Biological) attack, whole trains in the area are stopped by sensors, and also reduce air movement at the locations or stations (para. 3). Chemical detection systems put chemical sensors in action to prevent chemical attacks. By the new technologies, computer based security systems have minimized the terrorist attack scenarios and give no victims to them. In conclusion, subway systems are the most beneficial carrying system because they are technological, healthy and economical advantages. Subway systems which are the result of fuel and waste material produced are the most environmentally friendly transport. Subway systems are the ideal mode of transport in terms of time-money saving and accessibility for both people who live in cities and the managers of these cities. They are inspected more frequently than other transport systems and they are protected by the latest technology security systems. Thus, to have cheaper, more comfortable and safer travelling in daily life, subway systems should be expanded to every point in a city. Meanwhile, for a further research subway systems, to help the city’s development and create employment in the field of researches can be done.