I have some questions related to technical resignation.

Before coming to answer your query, I want to mention that please do not unnecessarily repeat the paras in your question as it does not add any value or increase clarity in your question. A concise and clear question will get appropriate answer rather than a clumsy one.

Anyway, coming to your query, I assume that you have applied for the police post through proper channel and your bank is aware of this development. Now you have been selected in police department and have to join the training after which you will be absorbed as a regular employee. When a person in one service applies for other position through proper channel and is selected then he is supposed to resign from the earlier post and it is known as technical resignation. This is an essential action as only after that you will be relieved to join the other department. You can not hold two positions simultaneously.

Now depending upon the joining date in your new assignment or position you have to give a one month notice to your present department and after one month you can join the new position as a trainee. In case you have to join early and that date can not be shifted to a later date then you will have to resign with immediate effect and I am afraid in such cases one has to deposit 1 month salary in lieu of notice period. So check with the HR of your bank regarding this rule. Once you join your new department even on training you are supposed to have started your new job and you will be getting the requisite stipend or salary during the training period. Subsequently on completion of training you will be absorbed as a regular employee.

From one government job to another government there is a facility of getting lien. But this facility is available if you have applied for the post through proper channel. When you have applied for the new job if we're not an employee in the present organisation also you can avail this facility provided when you have joined in the present job if you inform the employer about the job you have applied. This lien will be given by taking an undertaking that you will join back on or before the lien period. The lien is generally for 2 years but it may be given for 3 years in special cases.
But you are in a rural bank and this is not a direct government job but it S a government undertaking job, So this facility is not there for bank employees. You have to resign and join in the new organisation after resigning from the present organisation which nothing but technical resignation only. The relieving from the present job will be as per the rules and regulations and it will be governed by the terms and conditions of your appointment.

Your current job is in a different set up different from the proper direct government jobs. So if you have to join the proposed Police department job, you have necessarily resign from the current job complying the necessary guidelines and then getting proper relief and relieving letter.
The decision is to be taken by you whether to continue with the current rural bank job or to resign and join the new police department job training. But you can make some enquiries and if the trainees are called in batches or if there is any waiting list. (This may be more theoretical than actually practical). If it is available and if that suits you, you can make request to keep you in waiting list or for the later batches.

I think I have properly understood your question. Technical resignation (and consequently the facility of lien) is generally available to an employee only if the application for the second/subsequent job had earlier been sent through proper channel. I don't know whether you applied for the job in UP Police through proper channel, or not.

I would suggest you to intimate your present authorities (the rural bank) about your new job, submit the request for technical resignation and get the facility of the lien of two years. Request them to waive the condition of applying through proper channel (if not done by you) citing ignorance of rules.

I spoke to the Technical Resignation at the headquarters of the rural bank but he said that there is no such rule in rural bank. When I started asking, if you have any circular, then show us only if you give technical assessment. I did not find any circular of technical resignation in rural bank on Google. So what should I do now??

The main question in this case is: Did you send your application to the UP Police through proper channel? If yes, then you will automatically get the facility of lien. If not, then lien can be denied to you.