Wednesday, September 5, 2012

Indian Army - Canal Crossing Operation-II


In the previous post, I had presented a photo essay on  the canal/water crossing operations as practiced by the Indian Army during various exercises. To undertake such operations, right kind of bridging equipment is of utmost importance. In this post, I've tried to compile information about the bridging equipment of the Indian Army. In addition, we also take a look at videos of river crossing operations which show the sequence of various events.

Water obstacles crossing 

From what I've seen, such water obstacle crossing enterprise can be broadly divided into following components:
  • Secure the home bank of the canal.
  • Amphibious assault(s) across the water body to establish a lodgement and subsequently, a  larger bridgehead. The far bank of the water obstacle needs to be secured so that bridge can be put across and uninterrupted communication channel established. Needless to say, the forces which cross over need to be strong enough to first overcome the defenders and then guard against counter-attacks. These amphibious operations are undertaken by Infantry mounted on Infantry Combat Vehicles (ICV) like our BMP-2, in rafts of various kind and Main Battle Tanks (MBT) suitably modified to undertake such operations. Artillery support to suppress/eliminate the defenders and counter-battery fire is a must. In addition, air-support is required to keep away the enemy air-force as well as to suppress/eliminate enemy's defenses and forces in the area. Self Propelled (SP) Air Defense systems like Tungushka and Akash SAM mounted on T-72 chassis are used to provide AD cover.
  • Bridging operations - Once the bridgehead has been established, a bridge of a suitable type is put across the water obstacle. The main body of troops can then cross over and dash towards the main target(s). The support troops and vehicles forming the logistic chain follow thereafter to sustain troops fighting in the front.
Rest assured, such major crossing operations will receive every bit of love and attention from the enemy. The enemy will try to foil any such crossing and the event where he cannot do so, he'll try to delay the operations as much as possible. The fate of a major operation, battle or even the war may depend on the success (or otherwise) of such planned crossings. The enemy will bring to bear every possible asset under his command on such an operation by Indian Army.


Check these videos to have a look at the anatomy of such water obstacle crossing operation(s).

(a) Video 1 - Russian Army River crossing exercise.

The sequence of events in the video might not be correct. However, you can observe the following:
  • Infantry crossing over in BMP-2 ICVs. The BMP-2s can be seen firing their co-axial machines guns while still in water. I haven't manage to find a video of BMP-2 firing its main 30mm canon during amphibious crossings.
  • A strong body of tanks crossing over using the snorkeling method. Combined with Infantry+ICVs, these will constitute the main force to secure a lodgement and beat back initial counter-attacks.
  • You can also see a flight of Mi-8s crossing over the river; these can be used to insert infantry or special forces behind the enemy's defenses on the far-bank of the river and assault these defenses from the rear.
  • The ubiquitous Mi-24 gunships can be seen in the video giving top cover to the forces crossing over. In any major crossing, these gunships will be used to suppress/neutralize enemy defenses on the far-bank as well take out enemy forces in deep.
  • One can also see the Su-25 'Frogfoot' in action. In my opinion, the role of Su-25 in our case will be carried out to limited extent by Mig-27s.
  • One can also see amphibious ferry vehicles carrying trucks across the river.
  • In the final section, the Russian Army engineers can be seen putting together a pontoon bridge which is steered in place by tug-boats.
  • Once the bridge is put in place, the main body of troops can be seen crossing over, including a  ZSU-23-4 or 'Shilka'. These are used to provide AD cover to the troops.
In my opinion, what is missing is tanks providing direct fire support from home bank of the canal to forces crossing over.

(b) Video 2 - Russian Army River crossing exercise.

This is also quite similar to the one posted earlier. However, certain aspects are show in more detail (though, there might be an issue with sequence of events here as well). For example:
  • Simulated attack by a flight of Su-25 'Frog foot' aircraft to soften up the defenses on the far-bank of the river.
  • The Mi-8 helicopters can be seen inserting troops on the far bank of the canal.
  • Tanks get in position on the home bank of the canal and provide direct fire support before the ICVs can cross over.
  • Tungushka seen providing air-defense on the on home bank of the canal
Here is the video:

Indian Army - Bridging Equipment

1. AM-50 Bridge
This was developed in erstwhile Czechoslovakia. This is a special wheeled vehicle for launching a mobile bridge over obstacles of 10 to 12,5 m in width, that can support vehicles of up to 50 tons. Obstacles of greater width can be spanned by up to 8 of these bridge layers.

The bridge construction is mounted on the chassis of a 8x8 TATRA-815 truck. It is equipped with central controlled air pressure in its tires and a protection system against chemical, biological and radioactive agents. The depth of a bridged obstacle can be from 2 to 6 meters.

Here are some excellent pics which show the AM-50 bridge in various stages of operation. Regrettably, I haven't comes across good pics of various system in IA colors, so I have used pics/videos of these systems in service with armed forces of other nations from the internet.

The following two images show how multiple units can be combined to put together a bigger bridge. The TATRA vehicle unloading the bridge in the pic is positioned on a already laid AM-50 bridge.The new bridge being laid is articulated with the existing bridge.

Here is a Czec Army video of the AM-50 Bridge being laid out.

2. Sarvatra

SARVATRA is a multi – span scissor launched fully fabricated bridging system which is carried on a TATRA vehicle and is used to cross the obstacles during advance of tank columns.

The equipment consists of a bridge superstructure, launching mechanism, hydraulic actuators and piers which are mounted on the carrier vehicle. The pier system forms the bottom support for the superstructure when launched.

Special feature of this bridge is the fully fabricated structure, efficient steering with twin cabin (front and rear) control, low weight combined with high strength and load carrying capacity, short launching time (One Set consisting of 5 bridges can be launched in 150 min.), can be launched up to 75m obstacles and  easy transportation

As the source of the above description suggests, L&T has played a crucial role in the development of this system and partnered with DRDO for the R&D.  However, instead of awarding the contract for production of this system to L&T, MOD gave the contract for the same to BEML.

Salient features of the system:

Salient Features
Load Class: MLC-70 - this means it can handle MBT Arjun
Single Span Length: 15/20 m
Multi-Span Capability: 75/100 m
Roadway Width: 3.45 m during transportation; 4 m during use
Span Height: 2.6 m to 6 m
Construction time: 15 minutes
Crew: 1 driver + 3

The height of the span is an important criterion as canals in Pakistan are of varying depth. From what I've been able to gather, the depth of the canals varies from 1.5 meters to 3 meters. For example, the 30 meter wide Lahore Canal has a depth of approximately 5 feet or 1.5 meters.

Here are pics of the system.

A single span  mounted on TATRA vehicle 

TATRA 815 platform for mounting Sarvatra Bridge. The rear cabin has controls to drive/manage the vehicle and assist in accurate laying of the bridge

Source: BEML
Excellent pics showing the multi-span capability of the system. In the pics below, the additional spans are being added to existing ones to create a bigger bridge (up to 75 meters). In the second pic, it seems that two spans have already been laid while third is being laid out.


Source: Frontline

T-72 tanks crossing a water obstacle using the Sarvatra Bridge. One can count that at least 4 x single spans (of 15M  each) have been used. So, the water obstacle is 50+ meters at the minimum.

3. Bridge Laying Tank 

Well, as the name suggests, these are tanks modified to carry bridges (of varying sizes) instead of a turret with main gun. The bridge is used to provide mobility across wet/dry obstacles.Generally, the main battle tank in the inventory is used for the purpose as it simplifies the logistic aspect. Wikipedia has a detailed write-up on the such systems.

From what I've been able to gather, Indian Army has three types of BLT in service. These are T-55 BLT, Kartik BLT and T-72 BLT. While DRDO has developed a MLC-70 BLT based on Arjun tank, the same may not be inducted into the service. I think the T-72 BLT has become the staple BLT of the army in recent years. I think as of 2010, an indent of 135 T-72 BLT had been placed by the army.

The bridge laying mechanism on these BLTs is of two types - (a) horizontal deployment or cantilever type (b) Scissor type. One advantage cited in favor of horizontal type of deployment is that it maintains a low silhouette thereby leading to lesser chances of discovery by the enemy. Arjun BLT is also a horizontal type BLT. 

Picture as they say is a worth a thousand words, so I guess a video should be worth couple of million words. Here is a video each of horizontal/cantilever type and scissor type BLTs deploying their bridges. As is the norm, there aren't any videos of IA on this subject matter as well. So, I have linked videos of equipment from other armies. By the way, a BLT is called AVLB (Armoured Vehicle Launched Bridge) in western literature. 

Scissor type BLT/AVLB

Horizontal/Cantilever type BLT/AVLB

Indian Army BLTs

a. T-55 BLT - As the name suggest, this BLT is based on a T-55 chassis. It can lay a bridge of 18m length which can support weigh up to 50 tonnes.

Video of MT-55 of Czech Army deploying it and then retrieving its bridge. Under normal circumstances, the vehicle will move aside to allow the traffic to pass through and then, retrieve the bridge from this, or other side of the gap

T-55 in IA service


b. Kartik BLT - This is a second generation BLT of the Indian Army and is based on Vijayanta tank chassis. It can lay a bridge of 20 meter span and 4 meter wide. It carry loads up to MLC-60. Wiki has a detailed article on the topic 

Here is an image of Kartik BLT

c. T-72 BLT - As per the 2011 Annual Report of Ministry of Defense (MOD), a Limited Series Production (LSP) of 12 systems was completed and handed over to the army. Army has placed an indent of 135 such vehicles which will be manufactured at Heavy Vehicles Factory (HVF), Avadi.


Crew: A team of 3 personnel, including the driver, with complete NBC protection.

Length & Width: 22 metres span and 4 metres wide, with each track way 1.64 metres wide.
Material: Light weight, high strength, weldable, self-ageing, aluminium zinc-magnesium alloy (RDE-40).
Bridge Weight: 8800 kg (19,404 lbs).
Launching: Electro Hydraulic (high pressure) scissoring type of launch.
Launch Time: Approximately 3 to 5 minutes, using either manual or automatic launch.
Modes of Launch: Manual, electro-mechanical and automatic.

Image of T-72 BLT:

d. Arjun BLT - As the name suggests, this BLT is based on Arjun chassis. The BLT can support MLC-70 class vehicles which includes the Arjun tank as well. There are two bridging options - 24m and 26m long bridges made of steel and aluminium, respectively. Unlike other BLTs in the IA, Arjun BLT uses the horizontal method of bridge deployment.

I think after the development of the technology demonstrator, no firm orders were placed by the army. As per the latest interview of Director, CVRDE, carried by the Force Magazine, IA has intimated that it will not be placing orders for Arjun BLTs.

Arjun BLT

Interestingly, there are videos of Arjun BLT (from same event - Techfest 2009 at IIT) which shows a portion of the entire bridge laying operation.

4. Pontoon Bridge - This system offers tremendous flexibility o in terms of length and depth of the water body which can be covered. In all the images and videos of river/water obstacle crossing that I've seen, Pontoon bridges are used to cover the gap.

In India, the Pontoon bridge is manufactured by  BEML and is based on technology acquired from Omnipol of Czech Republic. 

As per Jane's, the initial purchase of PMS system was directly from then Czechoslovakia and subsequently, ToT in favor of BEML was effected. The entire system comprises of TATRA 8 × 8 transport and launcher vehicles, TATRA 8 × 8 trucks with a portable roadway system for use at bridging sites, TATRA 6 × 6 mobile cranes, and MO-634 bridging boats and SP-5 trailers


The Pontoon Bridge Set is used by Army to transport military vehicles over water obstacles and marshy grounds. It consists of various members like mid-stream & shore for assembling a bridge over water obstacles. Mid-stream, shore & road laying members are loaded on BEML-Tatra vehicles thereby allowing for easy transportation of the equipments. The set is fully equipped for unloading / loading of the members and formation of the bridge within a short span of time.
The maximum load carrying capacity of the bridge is 60 tonnes. Mid-stream members are joined together to form the floating bridge. Shore members are connecting to the mid-stream members & serve as the transition section between the floating part and the bank. The bulldozer attachment fitted on the road laying truck is used for creating approached road, removal of obstacles etc. road laying members are used for consolidating on the soft soil terrain. Ferries can also be constructed by using Mid-stream & Shore members. The ferry can carry individual loads from one bank to another with the boats pushing it.
The boat loaded on the dolly is towed by a BEML-Tatra vehicle. Dolly is equipped with the system for launching the boat as well as loading the boat back. The boat is used for pushing / towing the pontoon members for the bridge construction as well as for pushing the ferry.
The truck mounted crane is used for loading / unloading of various members both at launching as well as in the maintenance work shops.
Shore Pontoon segment
 Mid-stream Pontoon segment
Tug-Boat: BO-634 - this is used to set the alignment of the bridge in place and push/pull sub-components together to form a larger bridge. These boats can push/pull sub-components with load (like trucks, tanks, guns etc) and use the Pontoon System as a ferry.

Here are two excellent videos of pontoon bridges being put together.

(a) 1st Armored Division (USA) Bridge over the Sava River (Operation Joint Endeavor) - you can listen to the commentary in the video to get an overview of such operations.

(b) Pontoon bridge being laid by Hungarian Army:

In the video, you can see various sub-components being put together by the boats. You can also see the boats placed against the bridge at regular intervals to ensure that sub-components don't fall out of alignment due to water current or vibrations induced by the movement of the vehicles. The length of the bridge seems pretty long and the aerial shot is quite amazing.

The video of IA Corps of Engineers linked in the previous post has sections which show glimpse of laying of AM-50 and PMS Pontoon Bridge system.

5. Manually Launched Assault Bridge:

I've been able to get only one detailed reference to this system with one small picture. The pic is shown below:

Development - The Manually Launched Assault Bridge (MLAB) was designed and developed by the Research and Development Establishment (Engineers) at Dighi, Pune. It is in service with the Indian Army as an assault bridge as well as a line of Communication Bridge and can be delivered in several bridging kit configurations to meet requirements.

Description  - The MLAB is fabricated of a lightweight, high-strength weldable, self-ageing aluminium zinc-magnesium RDE-40 alloy capable of withstanding extremes of temperature and humidity. The heaviest component can be carried by a team of six personnel, while palletised loads can be configured for truck transport or for slinging under helicopters such as the Mil Mi-17.

For vehicle transport, a standard three-tonne pallet is used.The MLAB is a deck-type two-girder bridge system involving a fully modular, pin-jointed structure with inter-locking components, providing a 4 m-wide roadway. A standard double-storey bridge can bridge gaps up to 31 m (MLC 60). If longer gaps are encountered, this can be extended to 49 m using ancillary reinforcement equipment. If MLC 70 is required, shorter spans can be constructed. A single-span MLAB is constructed using two parallel girders consisting of top panels, each 1.83 m long.

With the addition of deck panels and bank-seat beams, bridges of MLC 60 at 9.8 m span and MLC 16 at 22 m span can be constructed.By adding bottom panels to single-storey girders during construction, the girder depth is increased and strengthened to form a double-storey bridge, capable of carrying MLC 60 vehicles over a 31 m span or MLC 16 vehicles over a 49 m single span.

A Link Reinforcement Kit (LRK) can enhance the load carrying capacity to MLC 60 for a 49 m span. Construction crew and times (MLC 60 bridge)

Added later (on 7th August ,2012): A fantastic link which gives details about similar system in British Army was shared by someone who left a comment on this blog entry. I'm putting the same below for reference:

It also has details about other engineering systems used by the British Army. Good reference point if someone wants a still deeper understanding of these things.

6. Short Span Bridge:

R&DE(E) is developing a short span bridge of 5 m and 10 m, which can be connected to the existing Sarvatra bridges or can be launched independently to bridge smaller gaps.

I think this has been inducted into the army.

7. Other systems - apart from the bridging equipment listed above, there is another very exciting system which has been showcased during Republic Day Parades. Amphibious Floating Bridge and Ferry System (AFFS) is listed as 'achievement' on DRDO website but I haven't come across news item confirming induction of this system in the army. If anyone has better information, please do share. 

Details of the system:

This 42 tonne mammoth is the Amphibious Floating Bridge and Ferry System (AFFS) developed by the R&DE (Engineers) branch of DRDO, for the ferry of traffic across large and deep water obstacles. The 10m x 3.6m x 4m vehicle can covert to a fully decked bridge configuration of length 28.4 metres, in 9 minutes. 

Two more vehicles can be joined in tandem to form a floating bridge of length 105m, in 30 minutes. The bridge superstructure is integrated with floats (shown inflated) to provide stability and additional buoyancy. The vehicle has a maximum speed of 55 km/h on road, 40 km/h cross country and an aquatic mobility of 2.7 m/sec with twin pump jets. The vehicle is also capable of retracting it's wheels for use as a grounded bridge/ramp for high banks.

Images of the system:

While I've not come across much details about this system apart from what I've shared here, there is one comparable system with French Army. It is known as EFA (Engin de Franchissement de l'Avant) or Forward Crossing Apparatus. The image is linked below.

You can check the details of the system here to get an idea about what AFFS is capable of doing:

There is an excellent video in the lower part of the web-page linked above which shows the deployment and use of this system. Multiple systems can be combined to form a bridge or ferry their payload (on captive power) towards the far bank of the water obstacle. This is like a pontoon bridge with power.


Anonymous said...

The third uncredited photograph under MT-55 is not an MT-55 bridge. The difference, between this and the previous two photos, is stark and telling.

Anonymous said...

For more information, images and video on what is shown here as MLAB, you can see Medium Girder Bridge.

Rohit Vats said...

To anon@9:22pm - now that you have mentioned it, yes, the bridge looks different. But the chassis is that of a T-55....jut check the number of road wheels and absence of side-skirts and compare with the previous two pics of T-55 BLT. So, even if the bridge has been modified, it still remains T-55 BLT. BTW, I don't think IA follows the MT-55 designation.

Rohit Vats said...

To anon@10:25pm - thanks for sharing the link. It is very helpful and educative. I'm adding the link to the post so that others can too have a look.

Anonymous said...

It is called MT-55 (Mostini Tank - Bridge Tank). The indian version is MT-55KS.

It is true that MT-55 are based on chassis/hull of T-55. What i said was "third photo is not an MT-55 bridge" without reference to the tank.

Anyway, good work.

Rahul M said...

Rohit, I think the pontoon and amphib bridges were featured in the natgeo series on army.

good work overall !

Rohit Vats said...

The earlier post on Canal operations that I wrote has the video on the Corps of Engineers linked in shows the AM-50 bridge and Pontoon bridge operations...

bennedose said...

Rohit I want to talk about Aksai Chin