Marine and rail engines made in India: who builds what

India builds diesel locomotives in Varanasi and marine engines from 14 HP up to about 1,200 HP, and assembles German-designed naval engines of up to 4,300 kW in Ranchi. Kirloskar Oil Engines is also designing a 6 MW ship engine for the Indian Navy. Here is who builds what, how big these engines are, and how to compare their ratings.

Who builds diesel locomotives in India?

Banaras Locomotive Works (BLW) in Varanasi, which started as Diesel Locomotive Works in August 1961. Its first broad-gauge locomotive, a WDM-2, came out in January 1964. In April 2002 it turned out its first 4,000 HP WDG-4 freight locomotive, and in June 2002 its first 3,300 HP WDG-3C.

By its own count, BLW had built 10,270 locomotives of all types by 31 May 2024. That includes 5,031 ALCO-type diesels, 2,467 high-horsepower (HHP) diesels, 1,953 electric locomotives for Indian Railways and 172 for export. The works says it has turned itself from a diesel maker into an electric locomotive maker.

Diesel has not stopped completely, though. The export orders are still diesel:

• Mozambique, current order: ten 3,300 HP AC-AC diesel-electric locomotives for CFM, Mozambique's national railway, placed through RITES. They run on cape gauge (1,067 mm) track at up to 100 km/h. The sixth was dispatched on 15 December 2025.
• Mozambique, earlier order: six 3,000 HP cape-gauge locomotives.
• Other buyers: BLW has also supplied locomotives to Sri Lanka and Myanmar since 2014.

A diesel-electric locomotive does not drive its wheels from the engine directly. The diesel engine turns an alternator, and electric motors on the axles move the train. The engine itself works on the same four strokes as any diesel, as our explainer on how a diesel engine works shows.

What else on the railways runs on diesel?

Power cars and track machines. Cummins India reports its rail business inside its domestic Industrial segment. On its call after the June 2026 quarter, the company said rail demand was coming from orders for power cars and for diesel-electric power cars used to lay and maintain overhead electric lines. Summaries of that call put the quarter's rail sales at ₹145 crore and marine sales at ₹50 crore, out of ₹458 crore of domestic Industrial sales. The company's quarterly results are on its Cummins India page.

What engines do Indian ships and patrol boats use?

At the large end, mostly imported ones. Garden Reach Shipbuilders & Engineers (GRSE) said so plainly when it signed a memorandum of understanding with Rolls-Royce Solutions of Germany on 27 January 2023. The deal covers licence production and localisation of MTU Series 4000 marine engines, rated 746 to 4,300 kW. These engines power fast patrol vessels, interceptor boats and fast attack craft built by GRSE and other Indian shipyards. GRSE's release said that "so far, these engines are imported", which lowers the Indian content of those vessels.

Under the agreement, the engines are to be assembled at GRSE's Diesel Engine Plant in Ranchi. The technology transfer covers assembly, painting, parts sourcing and after-sales service.

At the small and middle end, Kirloskar Oil Engines (KOEL) lists its own marine range on its defence products page:

Engine type	Maker	Power range
Marine propulsion engines	Kirloskar Oil Engines	23 to 1,210 HP
Marine auxiliary engines	Kirloskar Oil Engines	14 to 82 HP
Marine gensets	Kirloskar Oil Engines	10 to 1,010 kVA
MTU Series 4000 (licence assembly)	GRSE, Ranchi	746 to 4,300 kW
Navy medium-speed engine (in development)	Kirloskar Oil Engines	6 MW prototype, 3 to 10 MW family

What is the Navy's 6 MW engine project?

On 2 April 2025 the Indian Navy signed a project sanction order with Kirloskar Oil Engines to design and develop a 6 MW medium-speed marine diesel engine. The details from the government's release:

• Value: ₹270 crore, with 70% of the funding from the Government of India.
• Route: the Make-I category of defence procurement, where the government co-funds development.
• Content: the prototype is expected to have over 50% indigenous content.
• Scope: detailed design of an engine family from 3 to 10 MW, for main propulsion and power generation on Navy and Coast Guard ships.

KOEL's chairman told shareholders at the August 2025 annual general meeting that the selection places the company "in the middle of India's self-reliance journey in defence technology". KOEL's latest results are on its company page.

How big is a 6 MW engine? A worked example

Rail ratings are in HP, ship ratings are often in kW or MW, and gensets in kVA. To compare them, convert to one unit. One kW is about 1.341 HP.

• The Navy prototype: 6 MW = 6,000 kW × 1.341 = about 8,050 HP.
• The top of the MTU Series 4000 range: 4,300 kW × 1.341 = about 5,770 HP.
• The bottom of that range: 746 kW × 1.341 = about 1,000 HP.
• KOEL's largest listed marine propulsion engine: 1,210 HP ÷ 1.341 = about 900 kW.
• BLW's export locomotive: 3,300 HP ÷ 1.341 = about 2,460 kW.

So the 6 MW engine KOEL is designing would put out about 2.4 times the power of the 3,300 HP locomotives going to Mozambique, and about seven times its own largest marine engine on sale today. kVA ratings on marine gensets are a different measure again; our genset sizing guide explains how kVA becomes kW.

Why are these engines hard to see?

They sit inside hulls and locomotive bodies, they are bought by railways, navies and shipyards rather than by shops, and the big ones are built in small numbers to order. Most of the figures above come from defence releases, export dispatches and results calls, not from product catalogues. Makers' public pages give ranges, not prices.

Sources: Banaras Locomotive Works, Brief History and Heritage Diesel Locomotive pages (blw.indianrailways.gov.in); Press Information Bureau releases of 16 December 2025 (Mozambique 3,300 HP locomotives) and 2 April 2025 (6 MW marine diesel engine project sanction order), and the PIB release on the first 3,000 HP cape-gauge locomotives for Mozambique; Indian Infrastructure, 18 December 2025; GRSE disclosure to NSE and BSE, 28 January 2023, with its press release on the Rolls-Royce Solutions MoU; Kirloskar Oil Engines defence products page (kirloskaroilengines.com) and Chairman's speech at the AGM, 7 August 2025; Cummins India June 2026 quarter earnings call as summarised by Cofacto. HP and kW conversions are our arithmetic.