If project schedule is behind with engineering issues how we could solve the issue and put the activity on right track?

Resoursec increase and optimization will help  

Firstly we make a list of issue who make us behind to make the schedule then we recheck all details and start the work with full knowledge 

Restructure your priorities to sync with the Engineering designs

Find the means and measures to expand the output within the engineering confines to expedite the work.

Resoursec increase and optimization will help  

With respect this is not my scope, although, i can answer with re-desging the project schedule contains activity.activity.

Proceed to other activities where there are no engineering issues to maintain the target milestone. Resolve the engineering issues immediately to prevent further delay of execution.

while designing a work schedule for any project different activities are arranged and there kept an option for slack time for the sack if some how  work is not going as planned, this slack time is kingd of back up plan.

if you have not consider this, then obviously you have to reschedule your planning activities for a certain project and update it according to time required estimation for each activity

Complete Project Cannot go behind the schedule due to engineering activities and also don't expect to start the Project by completing the Engineering. You may need to breakdown the project in to micro level , then you may find so many activities which can be completed even before finalizing the Engineering . Please try and try to speak to expert to find better solution, since no idea what kind of project you are talking about clear answer cannot be given .

There are a handful of topics that have to be considered when trying to get a project back on schedule. First, is it reasonable to assume the current team will continue working at the same pace? If there was nothing out of the ordinary that occurred during the first phases of the project to put it behind schedule, this is probably a reasonable assumption. If this is the case, there are a couple of options available:

• Ask the team to work overtime until the schedule is back on track (potential cost impacts if the team members are not salaried employees)
• Add additional resources (will increase cost)
• Fast-track the schedule (not always possible and increases necessary communication)

Fast-tracking the schedule by completing tasks in parallel is not always a possibility, depending on the workflow process, but it can save the schedule without impacting the budget. I would start by reviewing the internal processes to see if any tasks can be completed in parallel, without significantly sacrificing efficiency. If that isn't possible, talk to the client/contractor to see which deliverables are needed first and which deliverables can be delayed. Often times, the contractor doesn't need a full engineering package to begin work, they only need one section of the project. 

By working Extra times with Engineers that know how to raise you up again

All the engineering issue has got fixed std time to accomplished.  Estimate will all DFEMA, PFEMA.