HEMU-430X (standing for High-Speed Electric Multiple Unit 430 km/h eXperimental) is a South Korean high-speed train intended for a maximum speed of . On March 31, 2013, it achieved  in a test run, making South Korea the world's fourth country after France, Japan and China to develop a high-speed train running above . The main new feature of the train compared to older South Korean high-speed trains is distributed traction.  The commercial versions of the trains, tentatively named the EMU-260 (as of October 2022, officially "Eum") and EMU-320, were delivered to Korail from 2020 to 2021.

History

The original 1991 plan for the Korea Train Express (KTX) high-speed rail system foresaw an operating speed of  to enable a travel time under two hours between Seoul in the northwest and Busan in the southeast of South Korea, the termini of the first line.  Later, planned top speed was reduced to the  maximum of existing high-speed trains on the market. Korail then ordered high-speed trains on the basis of Alstom's TGV Réseau, the KTX-I, which started KTX service on April 1, 2004, and operate at a top speed increased slightly to  in November 2007.

In a project, South Korean government research institutes and rail industry companies were directed in 1996 to fully localise high-speed rail technology. The know-how gained in the technology transfer for the KTX-I was used as the basis to develop the experimental train HSR-350x, which was to be tested at up to  so that the commercial version could have a top speed of .  However, the maximum speed achieved in the HSR-350x tests was  on December 16, 2004; and the design and top speeds of the commercial version, the KTX-II (KTX-Sancheon) were set to be the same as those for the KTX-I.

The aim to develop commercial trains with a top speed of  was taken up again in the project to build another experimental train, the HEMU-400X (High-speed Electric Multiple Unit - 400 km/h  eXperiment), which was launched in July 2007.  The six-year project schedule was originally set to last until July 2013, and involved  of test runs with speeds reaching .  The project is led by the Korean Railroad Research Institute (KRRI) and Hyundai Rotem, and also involves the Korea Institute of Construction & Transportation Evaluation and Planning (KICTEP), 20 other companies, 13 universities, and one other organisation. The project budget was set at 97.11 billion won, with a government contribution of 69.2 billion won.

Following a call by Nam-Hee Chae, the president of the Korea Railroad Research Institute, for proposals for a generic name for Korean-made high-speed trains, on April 5, 2007, Chae announced the name Hanvit (Hangul: 한빛), which means a streak of intense light in Korean.  Under the new naming scheme, HEMU-400X is also called Hanvit 400.

The preliminary design was presented to the public in May 2009.  A full-scale mock-up of an end car was first shown in June 2009 at the RailLog 2009 exhibition in Busan.  Detailed designs were presented in October 2010, when the prototype was expected to be completed in 2011 and start line tests in 2012.

HEMU-430X prototype
A prototype, named HEMU-430X was unveiled in May 2012. The unit is expected to undergo around 100,000 km of testing up to 2015.

Technical details

In contrast to the articulated passenger coaches between traction heads configuration of the KTX-I, HSR-350x and KTX-II trains, the 6-car HEMU-400X is fitted with distributed traction: traction equipment is underfloor and all axles of all four intermediate cars are powered.  The detailed plans released in October 2010 changed the trailing end driving trailer of the experimental train into a powered car, deviating from the planned commercial version.  The new high-power configuration is to provide for higher acceleration: the 8-car commercial configuration was calculated to reach  in less than four minutes and less than ; the top test speed of  is to be reached in 673 seconds and .  Similarly to JR East's Fastech 360 programme, the plan is to develop and test both asynchronous induction motors and permanent magnet synchronous motors in the train.

Research in the G7 programme showed that the bulk of the longitudinal aerodynamic resistance (drag) of the pantograph and the largest component of vertical aerodynamic forces (lift) acting on it derive from the contact shoe.  For the HEMU-400X, researchers developed an aerodynamically optimised contact shoe cross section that reduced drag by about 40% and lift amplitude by about 25% in comparison to the contact shoe of the KTX-II pantographs.

The train is designed with active suspension for increased ride comfort.  To save weight, in addition to aluminum, composite materials are to be used in the carbody.  The development of new transformers, batteries and a number of other electric system components also focuses on reducing weight and size.  The train is also intended as basis for Rotem to compete in high-speed train tenders abroad, and is designed to conform with European high-speed rail standards.

Nose styling was designed using a genetic algorithm, starting with the hybridization of the nose shapes of existing French TGV and German ICE high-speed trains.  A double-deck configuration was also considered.

In the experimental train, the first two cars will test first class seating, the fourth car will be fitted out with a bar and special passenger compartments, the fifth car will test standard class seating.  Data acquisition equipment for the on-board measurements are foreseen in the third and sixth cars.

Commercial version (EMU-260/320)

EMU-260/320, formerly known as KTX-III, is the commercial derivative of HEMU-400X . It is expected to enter service in late 2020 or early 2021.  According to the initial information, In normal 8-car,  configuration, KTX-III would consist of two driving trailers at either end and six motorized intermediate cars giving 9.84 MW of power, with an option of extension to 10 cars.  The second, fourth and seventh cars will house transformers, each connected to inverter groups on the neighbouring third, fifth, respective sixth car.  The end cars will house the batteries, while pantographs will be installed on the extreme intermediate cars.

The goal for maximum operating speed was originally , which was expected to enable Seoul-Busan travel times of 1 hour 50 minutes.  In plans released in October 2010, planned service speed was raised to .  In the default configuration, the first two cars will be first class with 2+1 seating, the third car will house a bar and special passenger compartments with facing pairs of 3 or 2 seats, the fourth to eighth cars will be standard class with "3" seating, with foldable seats offering altogether 378 seats.

In September 2016, the designs of the EMU-260 and EMU-320 were decided, and it was known that the EMU-260 and EMU-320 will share the same design but with different patterns .

In May 2017, the EMU-260's mock-up and interior design were released to the public, and public opinion on the mock-up and interior design was collected .

The first EMU-260 was released in November 2019 into trial operation .

References

High-speed trains of South Korea
Korea Train Express
Train-related introductions in 2011
Experimental and prototype high-speed trains
25 kV AC multiple units
Hyundai Rotem multiple units
HEMU-430X(Highspeed Electric Multiple Unit - 430km/h eXperiment)는 한국철도기술연구원(KRRI)의 주도로 한국건설교통기술평가원 등이 참여하여 진행 중인 차기 고속철도 시제차량 제작 및 기술 개발 프로젝트다. 이전에는 HEMU-400X라는 이름을 사용하였으나, 이후 설계최고속도가 30 km/h 증가하면서 현재의 이름으로 바뀌었다.

영어로는 HEMU라고 쓰고, 한글로는 해무라 쓴다. 한글 표기 해무에 대응되는 한자 표기에는 두 가지가 있다. 먼저 상서로운 바다 안개를 뜻하는 海霧와 빠르게 달린다는 韰騖가 그 뜻에 해당한다.

개요 
이 열차는 설계최고속도 430km/h, 영업운전속도 370~400km/h를 목표로 개발중인 고속철도 차량이다. 평탄선 균형속도는 시속 444km/h라고 한다 2007년 4월부터 2012년 7월까지 총 5년간 개발이 진행되었으며, 투입 예산은 931억원이다. 차량 가격은 1편성(8량) 당 382억 3000만 원이다. 현재 국내개발 고속철도 중에서 가격이 가장 비싼 차종이다.

기관차가 객차를 견인하는 방식인 동력집중식 고속열차 KTX나 KTX-산천 차량과는 달리, 큰 점착력이 요구되는 300km/h 이상의 고속 주행에 적합한 최초의 동력분산식으로 설계되었다. 이를 통해 수송력 강화와 가감속 성능 향상 등도 달성하고 있는데, 예를 들어 정차 상태에서 300km/h까지 가속하는 데에 KTX는 6분 5초, KTX-산천의 경우 5분 16초가 걸리는 데에 비해 이 열차에서는 3분 53초까지 줄어들었다. 또한 제동 성능도 KTX-산천의 23MJ에서 43MJ로 향상되었다.

또 동력분산식 설계의 채용에 의해 기관차가 제거됨에 따라 선두·후미 차량에도 승객 탑승이 가능해져 편성 당 정원이 KTX-산천의 363명에서 456명으로 16%가량 늘었다. 좌석 간 간격은 특실 1,120mm, 일반실 1,000mm으로 특실은 KTX, KTX-산천과 동일하며 일반실은 KTX에 비해 70mm, KTX-산천에 비해서는 20mm 더 길다.

기술

차체 
차체는 KTX-산천과 같은 알루미늄 더블스킨 구조로 되어 있다. 그러나 구조의 최적화로 KTX-산천 대비 중량이 5%정도 경량화되었으며, 차음 성능 또한 5dB까지 향상되었다.

전원·제어 기기 
시험차량의 구동장치로는 기존의 유도전동기와, 유도전동기에 비해 소형이면서 효율이 좋은 영구자석 동기전동기 양쪽 모두를 사용하며, 유도전동기는 2~5호차에, 영구자석 동기전동기는 부산 방면 최후미차인 6호차에 설치되어 있다. 출력은 두 방식의 전동기 모두 410kW로, 동력차에는 이를 4기씩 탑재하여 량당 출력은 1,640kW이다. 양산차량에는 시운행 기간 동안 시험차량에 사용된 양 전동기에 대해 종합적인 평가를 실시하여 보다 적합한 쪽이 채용될 예정이다.

시험차량의 차량 배치는 Tc+M1+M2+M3+M4+Mc의 5M1T로 구성되어 있으며, 이 중 Mc차량은 위에서 서술한 영구자석 동기전동기(1C1M 제어) 적용 시험을 목적으로 특별 제작되어, 이 1량만이 편성 내의 다른 차량과는 독립된 주회로 시스템을 가지며 이를 위해 객실 내에 일부 장비를 탑재하고 있다. 양산차량은 시험차량과 달리 구동계가 통일되므로 Tc+M1+...+M6+Tc의 6M2T로 구성되어 있다.

대차 
대차는 ITX-청춘 열차에서도 사용된 방식인 링크암 식 볼스터리스 대차를 채용했다. 고속화에 따른 진동 증가에 대응하여 쾌적한 승차감을 구현하기 위해 보통 대차의 옆면에 1개씩 설치하는 요댐퍼를 양 옆으로 2개 설치하였으며, 차체의 롤(Roll)을 막아주는 안티 롤 바가 설치되어 있다.

대한민국의 철도차량으로서는 최초로 세미 액티브 서스펜션이 설치되었다.

향후 
2009년 2월 17일에 국토해양부에서 외형과 실내 디자인 시안이 발표되었으며, 2012년 5월 16일에 경전선 창원중앙역에서 시제차량을 출고하였다.

출고 이후 10개월 동안 총 138회의 증속시험을 통해 2013년 3월 28일 오전 3시 2분 46초에 최고속도인 시속 421.4km를 기록했다. 한국철도기술연구원에 따르면 유지보수 시간 확보의 어려움 때문에 더 이상의 최고속도 증속보다는 부품 신뢰성 검증 등 안정화 테스트를 주로 할 것으로 알려졌다.

2024년에 평택 - 오송간 고속철도 노선에서 시속 400km/h급 열차를 상용화한다고 한다.

개발 진행 현황 
 2007년 9월 6일에 KRRI의 주최로 차세대 고속철도 기술개발사업 착수 보고회가 개최되었다.
 2010년 9월 1일에 미래 녹색국토 구현을 위한 KTX 고속철도망 구축전략에 따라 사업기간이 1년 단축되고 목표 최고속도가 430 km/h으로 상향 조정되었다.
 2012년 12월 27일에 시험구간 속도 400 km/h를 돌파하였다.
 2013년 3월 28일에 시험구간 속도 421.4 km/h를 돌파하였다.

사진

같이 보기 
 KTX-이음

각주

외부 링크 

 차세대고속철도 개발사업단 홈페이지 연구성과 소개 페이지

대한민국의 고속철도 차량